Copyright DASSAULT SYSTEMES CATIA Training Foils Digitized Shape Editor Version 5 Release 8 February 2002 EDU-CAT-E-DSE-FF-V5R8

Copyright DASSAULT SYSTEMES Prerequisites: Fundamentals about CATIA V5 Objectives of the Course In this course you will learn to use digitized data Targeted audience Designers Reverse engineers Course Presentation 1 day

Copyright DASSAULT SYSTEMES Table of Contents 1. Introduction to Digital Shape Editor p.4 Quick start: Demonstration or discover itp.5 Workbench Presentation p.6 2. Fundamentals of Digital Shape Editor p.14 Point Processingp.15 Faceting the Cloud of Points p.23 Creating Curvesp Advanced Lessonp.38 Point Processing p.39 Tessellation and Offsetp.48

Copyright DASSAULT SYSTEMES Introduction to Digitized Shape Editor In this lesson we will have an overview of the capabilities of Digitized Shape Editor Quick Start Workbench Presentation

Copyright DASSAULT SYSTEMES Quick Start Short Demonstration to position DSE in the global process You will get an idea of what you can do with the product... From Physical part to Digital model

Copyright DASSAULT SYSTEMES Accessing Workbench Exploring the User Interface Glossary Understanding Terminology Workbench Presentation (1/8) In this lesson, you will learn about the Digitized Shape Editor Workbench by

Copyright DASSAULT SYSTEMES Workbench Presentation (2/8) 1- Start 2- Shape 3- Digitized Shape Editor At any time, the current workbench is indicated by an icon on the right hand side of the screen. Accessing the Workbench

Copyright DASSAULT SYSTEMES The User interface (1/6) Workbench Presentation (3/8) Digitized Shape Editor Tools... Part tree Standard tools Features... Compass

Copyright DASSAULT SYSTEMES Workbench Presentation (4/8) The User Interface (2/6) Digitized Shape Editor tools

Copyright DASSAULT SYSTEMES The compass is used to: 1- Select a plane/direction to perform an action 2- Display according to a main plane 3- Apply a transformation to one or several entities. Position the compass : You may Drag and Drop your compass to: A curve: you will define the plane normal to the curve A surface: you will define the plane tangent to the surface where you dropped the compass The compass is then switched from x,y,z to a u,v,w trihedron Then hitting a Pop up menu you will flip from u,v to v,w then w,x plane definition Compass set up: A contextual menu is associated to the compass, it allows to Lock the position to given state (current or screen orientation) Make one principal plane the privilege plane Automatically attach the compass to the entity you select x,y,z is switched to a u,v,w trihedron when attached to an object Reset Compass: You may reset the compass by: Using menu View then Rest Compass Or Drag and Drop the Compass on the xyz trihedron The User Interface (3/6) The Compass Workbench Presentation (5/8)

Copyright DASSAULT SYSTEMES Workbench Presentation (6/8) The User Interface (4/6) Glossary (1/2) This function is used to define a particular portion of a cloud for further operations.Activate Align Cloud of Point Digit Filtering Neighborhood Remove Scan This function is used to reposition several digits to each other in order to reconstruct a complete object. A cloud of points is defined as a set of points in 3D space. It may consist of a single point or several million of points. Those points may be the result of a digitizing or of a computing operation. In the current manual, the term cloud of points refer to several representations: representation as a set of points, representation as a set of lines of points (or scans), representation as a set of grids, representation as a tessellation (or mesh, or polygon). A cloud of points may consist of several digits (i.e. sub-clouds). Filtering a cloud of points is a method to create a lighter working context: some points are hidden, thus Making further operations on the cloud quicker. Those hidden points can be recalled later. Many functions in Digitized Shape Editor operate on the points in space, regardless of the organization of the data in the cloud. In these functions, you can specify a maximum distance (neighborhood) which will be considered around a point for the operation. The larger the neighborhood value, the more points will be considered, and possibly the operation may become slower. A default neighborhood value is proposed in those functions. This function deletes physically points from the cloud of points. The points can not be recovered. A scan is a polyline made of ordered series of Points. It often represents curves via series of points. Cloud of points can be organized in consecutive scans.

Copyright DASSAULT SYSTEMES Workbench Presentation (7/8) The User Interface (5/6) Glossary (2/2) This operation is performed while importing a cloud of points. You can choose to import only a percentage of the points of the cloud. Sampling Shading Tessellation Working Distance A tessellation can be visualized in shaded mode. This mode is a method for visualizing the point data and getting an impression of its quality. A tessellation (or polygon or mesh) consists of a set of polygonal faces which represent the surface of a 3D model. A triangulation is computed to describe the neighborhood relation of all points. A tessellation can be used to check the quality of the points, or can be processed in other CATIA V5 applications. This is the distance beyond which the operation will have no effect.

Copyright DASSAULT SYSTEMES Workbench Presentation (8/8) A Part is a combination of one or more features, and bodies A Open body is a set of Geometrical Elements. You will be able to divide your car in different Parts. Geometrical Elements are Cloud Import, Planar Sections, Cloud Tessellation and Curves. The User Interface (6/6) Terminology

Copyright DASSAULT SYSTEMES Fundamentals of Digital Shape Editor Master exercise: CAR Door In this lesson you will learn how to create a new model of hairdryer from scratch, straight from the design idea you have in mind Presentation of the exercise: Car Door Point Processing Faceting the cloud of Points Creating curves Exporting the result

Copyright DASSAULT SYSTEMES Importing the Point Data Cleaning the Data Reducing the amount of Data In this lesson you will learn how to decrease the number of points of your model Point Processing

Copyright DASSAULT SYSTEMES Importing the Point Data (1/2) Cloud import (1/2): In this application you work from digitized Data. The first job is to import this data inside CATIA You get a standard Windows Dialog box that will allow you to select one (or several) file(s) The displayed files are compliant to the Format field (*.* to display all file names). Selecting the file(s) to import : You have the choice among a wide range of standard formats. A more buttons shows up according to the selected format, it allows more parameterization Format : Direction and Delimiters apply to scans. Enter this data whenever you know it. Minimal Point Quality is used to clean Atos file from invalid points. The quality value of a point lies between 0 and 255 (low to high). Choose a value to ignore points below that value. System applies to the operating system (Unix or Windows NT) used to generate the binary data: select Same if you know you are using the same operating system as the one used to generate the binary data, Other for the other way, Unknown if you have no indication. Free Edges is used to create or not the scans representing the free edges of a cloud of points. Facets is used to create or not the facets of the imported cloud of points If the extension of the file you have selected is consistent with the list proposed, the Format field is updated automatically. Otherwise, be careful to enter the correct format in that field. Once you have performed an import operation, Digitized Shape Editor proposes the last entered file path and format as default. If you click on..., the last entered directory is proposed as default. Ascii : Atos : Stl : Iges :

Copyright DASSAULT SYSTEMES Cloud Import (2/2) In this application you work from digitized Data. The first job is to import this data inside CATIA Sampling: allows to import a certain percentage of the Digitized data, be careful, this will be done sequentially every x points will be kept. Scale Factor: the scan is very often performed on a scaled model, you may want to work on real size model, apply the given scale factor File Unit: your CATIA session is set up for a given unit. The file you import comes from the outside world and may be digitized in another unit. Set up the proper unit before importing the file Options : Replace : will replace the current cloud of points by this new one. Update: Will display the cloud of points along with its bounding box. Then use the manipulators of this box to clip the part of the cloud you import Preview : The File unit option is not relevant to the Steinbichler format, nor the Sampling percentage to the Stl format. An element is created in the specification tree, under the name Cloud Import.x. Undo and Redo are available. Digitized Shape Editor memorizes the data of the last imported file and proposes them at the next import action.click on..., the last entered directory is proposed as default. If you import several Clouds of points in the same action, the result will be a single Cloud of Point entity This check box will allow you to get information in the statistics window (number of points, dimensions…) Statistics : Apply : when you are satisfied with your import parameters, use Apply then OK to create the Cloud Import entity Importing the Point Data (2/2)

Copyright DASSAULT SYSTEMES Remove: This action is used to remove points from the Cloud of Points Inside Trap: Outside Trap: Selected Part, it can be: Pick : will allow selection by picking elements on screen. The element type is filtered by the options from Level Trap: Will allow the selection through a contour trap see explanation on trap type. The trap is drawn in a plane but has a depth. Then you may change the trap by the manipulators of the Trap. Selection : The deleted points are those that appear in red during the selection By default, as shown above, the trap is displayed in the view plane. It is thus a 2D trap. You can rotate the model to display it as a 3D trap. You can modify the shape of the trap using the green arrows that appear on the edges of the trap. Removed points can not be recalled! Activate all and Swap apply only to the current removal action. They can not be used to recall removed points, once you have clicked OK Select all will select the whole Cloud of points Swap will switch the selection by the not selected elements Global : Level: In coordination with Pick can be set to: PointScan/Grid DigitCloud Triangle It can be either Rectangular or Polygonal trap contour Trap Type : You can create as many areas as you wish by clicking Apply and drawing another trap, until you click OK to validate and exit the action. Cleaning the Data (1/2)

Copyright DASSAULT SYSTEMES Filtering: Used to decrease the number of points in a Cloud of Points Homogeneous: enter the value of the Sphere radius, used to filter the points. The filtering sphere is visualized by a green sphere. You can change its position by a simple mouse click at a desired location Each time you click Apply, the cloud of points and the statistics are updated. Once you are satisfied with the result, click OK to confirm and exit the action The points are hidden, not removed. Within a filtering action, Undo cancels the last filter action performed. Leaving the action with Cancel restores the cloud as it was before starting the filtering action. Filtering with a radius equal to 0 cancels ALL filtering actions performed on the cloud of points: It is not possible to filter a tessellated cloud of points or a polygon. When you filter scans or grids, you actually filter points: filtered points are hidden, and new scans or grids are created. Homogeneous: the sphere passes over the cloud of points, starting on the first point met. All the points that are inside the sphere are then hidden. The sphere goes to the next remaining point and removes the points that it contains, and so on. In the result, 2 consecutive points will be at least distant from the Sphere radius. Adaptative: will use a local chordal deviation criterion. Principle : Statistics will be then displayed, that is : Before application, The number of points to be processed. After Application, the number, and the percentage of the remaining points When this option is checked, you will remove the points from your actual Cloud of Points (see erase menu) Physical removal : Adaptative : The value to enter represents the local chordal deviation. This filtering hides more points from the planar areas than from other areas. That way, you can highlight bent areas. Cleaning the Data (2/2)

Copyright DASSAULT SYSTEMES Activate: This action is used to define active set of points from a Cloud of Points Inside Trap: Outside Trap: Selected Part, it can be: Pick : will allow to select by picking elements on screen. The element type is filtered by the options from Level Trap: Will allow the selection through a contour trap see explanation on trap type. The trap is drawn in a plane but has a depth. Then you may change the trap by the manipulators of the Trap. Selection : The activated points are those that appear in red during the selection By default, as shown above, the trap is displayed in the view plane. It is thus a 2D trap. You can rotate the model to display it as a 3D trap. You can modify the shape of the trap using the green arrows that appear on the edges of the trap. Non active points are still in the Clouds of Point element, you can restore it when desired. If displayed as a shaded tessellation, the result will not be visible. You should display the tessellation as triangles to visualize the result Activate all will activate the whole Cloud of points Swap will switch the activated by the de-activated elements Global : Level: In coordination with Pick can be set to: PointScan/Grid DigitCloud It can be either Rectangular or Polygonal trap contour Trap Type : You can create as many areas as you wish by clicking Apply and drawing another trap, until you click OK to validate and exit the action. Reducing the amount of Data

Copyright DASSAULT SYSTEMES Exercise Presentation Illustration of the exercise step And now practice on the 1rst step of the Car Door exercise, to learn about: Importing Data Deleting Points from the Cloud Filtering the Data Activating part of the Cloud

Copyright DASSAULT SYSTEMES You have seen how to handle digitized Data within Digital Cloud Editor: Importing Clouds of points Removing points Filtering points according to criteria Activating part of the cloud of points Copyright DASSAULT SYSTEMES 2002 Point processing 1 To Sum Up

Copyright DASSAULT SYSTEMES Projecting a curve on the Cloud Tessellating the Cloud In this lesson you will learn how to tessellate the Cloud of points or scans Faceting the Cloud

Copyright DASSAULT SYSTEMES Projecting a curve on the Cloud Project Curves: Used to project 1 or several curves onto a Cloud of Points Discretization Number of Points: to be computed on the curve to be then projected on the Cloud of Point (non faceted cloud only). The curve is discrete in a number of points that are projected on the Cloud of Points according to a direction. The 3 closest points from the cloud are located. The result is the intersection of the closest facet with the direction of projection. The result is a Scan typed as Curve Projection Principle : Working Distance: The distance used to locate the points eligible to compute the 3 closest points to the projection. (non facetted cloud only) Try increasing this number if the result does not contain enough points Direction of projection: Linked to the compass The Projection is either performed Along the normal of the privileged plane Along the w direction if the compass is oriented according to a geometrical entity. Chordal error: For tessellation only. Chordal error used to create points to be projected onto the faceted cloud

Copyright DASSAULT SYSTEMES Tessellate: This action is used to create facets on the cloud of points using the active points Triangles: on or off Shading: on or off Display, you may choose : Neighborhood : The maximum length of the facet edge, if one edge of the facet is greater than this maximum, it will not be created Increase the Neighborhood value to improve the tessellation. In some cases, it may be difficult to find a Neighborhood value that will fill unwanted holes, without creating unwanted triangles.use the help of the displayed green sphere to set up this parameter. Seams may appear on the tessellation with the Smooth option, they indicate that the normals to the facets have different directions at this place. In Automatic mode, some triangles may overlap and tessellation should be corrected. In Manual and Constrained mode, they show the common boundaries of tessellations. When computing a constrained tessellation, enter 0 as the Neighborhood value to check the boundaries of the tessellation. If the boundaries are not satisfactory, modify the tessellation plane to improve them.After the computation of a constrained tessellation, two tessellation elements are visible in the specification tree: the constrained tessellation and the initial tessellation. You can select one and then the other to make sure they are complementary. A mesh is created on all the active points of the cloud The maximum facet edge is set via the Neighborhood parameter Principle : Flat: each triangle is lighted according to its normal Smooth: Triangle are lighted according to the average normal at each vertex. The result is smoothed and the display looks more realistic Type : Constrained, when tessellating part of a Cloud of Points: If some of the active points are already used in another tessellation, the computation of the new tessellation will take this tessellation into account to create a seamless result. Automatic: for a quick and rough creation of the tessellation. You will often get overlapping facets Manual: user selects the reference plane via the compass, a default value is proposed (mean plane of the cloud) Execution mode, directs the way the reference plane is chosen: Tessellating the Cloud

Copyright DASSAULT SYSTEMES Exercise Presentation And now practice on the 2nd step of the Car Door exercise, to learn about: Projecting curves on the Cloud Faceting the Cloud Illustration of the exercise step

Copyright DASSAULT SYSTEMES You have seen how to use digitized data to : Project curves onto the Cloud of Points (to further trim it) Create a tessellation (faceting) of your cleaned Point Data Copyright DASSAULT SYSTEMES 2002 Faceting the cloud of points 2 To Sum Up

Copyright DASSAULT SYSTEMES Creating Scan Section on the tessellation Creating curves from the Scan Drawing Characteristic lines on the tessellation Exporting the result In this lesson you will learn how to create section curves on the tessellation Creating Curves

Copyright DASSAULT SYSTEMES Planar Section (1/2) This action creates intersection of the Cloud of points by a family of planes. The result is a Scan. Number Number : enter the number of planes you want to process. infinite: the whole model will be processed using the fixed parameter. Step: enter the distance between 2 planes. From each plane using the influence Area distance the system computes a volume (yellow on the drawing) then select the points of the cloud inside this volume. From these points the system interpolates an intersection point. For a Tessellated model, the intersection is directly performed on the facets. The result is a Scan typed as Planar Section Principle : Fixed you have to fix on of the following Step: You choose to fix the distance between 2 planes. Number: you choose the number of resulting scans. Influence Area: thickness of the plane (N.A for tessellated model) Scans: the result will be one Scan per plane (Distinct) or a single Scan (Grouped into one element) Swap: it inverts the direction for the planes. Plane definition: sets the reference plane use main plane (yz, xz, xy), use the compass or use an existing plane. a manipulator is then available to move the reference plane along its normal. another manipulator is Available for the last plane. see next slide for Apply: displays the sections. OK: creates the resulting scans. Creating Scan sections on the Cloud (1/4)

Copyright DASSAULT SYSTEMES Planar Section (2/2) This action creates intersection of the Cloud of points by a family of planes. The result is a Scan. Although cutting a cloud of points is quicker (no need to tessellate first), creating planar sections on a tessellation rather than on a cloud of points has some advantages: 1- the action is dynamic on tessellations: no need to apply to visualize the modifications (position of the reference plane, step, number of planes,...), 2- In the case of a cloud of points, the intersection may be interpolated, since the plane does not necessarily intersect points. That problem is reduced with tessellations since the plane intersects facets, providing a better accuracy. The scans are created in the specification tree, as Planar Sections.x. The scans created are ordered. Scans can then be exported to an ASCII file. Section guide : select a curve: the sections will be perpendicular to this curve. The degree of the section guide must be greater than 2. Once the section guide is selected, the Limitation box becomes available. If required, you can select one or two limiting curves. Pick the first limiting curve, its name is displayed in the first curve field. You can then select a second limiting curve. Its name is displayed in the second curve field. The limiting curves should lay on the cloud of points. The section guide curve can be selected as second limiting curve (not as the first). To replace a limiting curve by another, uncheck the corresponding field: the name is erased. Check the field again and select the new curve. Its name is displayed Creating Scan sections on the Cloud (2/4)

Copyright DASSAULT SYSTEMES Cloud Display: This action changes the display of Cloud of Points. Today it may be very useful for Scans and Grid Cloud of Points. Point Symbol : Chose the marker for point display. Scan or Grid Polyline: displays the scan and grid selected connecting the ordered points by segments of lines. Point: whether yes or not the points are displayed. Tessellation only 3 options are available: Triangles: display of the facets Smooth: display in goureau shading Non-manifold edge have their edges displayed as regular white lines. The free edges displayed are those of the complete cloud of points (if you activate only a portion of a cloud of points, the free edges of that portion are not displayed). You can change the color of an element with the Properties menu of the element, in the Graphic tab Sampling You can also choose to display only a percentage of the points making the cloud, using the Sampling option. By default, 100% of the points are visible. You can change this value with the associated spinner. Creating Scan sections on the Cloud (3/4)

Copyright DASSAULT SYSTEMES Create Scans on Cloud : This action is used to create scans using points from the Cloud of Points. Very useful to draw characteristic lines manually. Select the Scan on Cloud icon and a cloud Click points on the cloud to create the scan Double-click to exit the action. A Scan_on_Cloud.x element is created in the specification tree. Undo and Redo are available for each pick. One single scan cannot be created over several clouds. If you press the Ctrl key wile moving the cursor on the cloud, the creation of the scan is displayed interactively. Ergonomics: Creating Scan sections on the Cloud (4/4)

Copyright DASSAULT SYSTEMES Curve from Scans: Used to build a curve from a (set of) Scan(s). Accuracy: sets the maximum distance between the original Scan points and the resulting curve(s). The min and max distance are displayed dynamically for each curve, changing the parameters will update these values. Degree: is the order of the curves created, i.e. the number of control points of those curves. Number: is the maximum number of spans between two cutting points. Smoothing Factor: if its value is 0, there is no smoothing. Increase this value to obtain a tenser curve. Split Angle is very useful to detect the sharp edges. Split Angle: This parameter is used to divide a computed curve in 2 curve according to an angle criterion. the angle of the 2 segments built on every 3 consecutive points is compared to this value. When bigger than this value, the computed curve is divided in 2 curves 2 methods are available: Smoothing: fit the points from the Scan(s) by curve(s) to a given tolerance. Interpolation: creation of a bi-spline passing through the points of the scan(s) : In case the method used is Smoothing, you may control some more parameters: Creating Curves from the Scan (1/2)

Copyright DASSAULT SYSTEMES Curve from Scans: Used to build a curve from a (set of) Scan(s). When the curve computed is segmented, the segmentation is displayed as yellow x symbols. This color and symbol are not editable. You can also add split points by picking points on the scan 2 methods are available: Smoothing: fit the points from the Scan(s) by curve(s) to a given tolerance. Interpolation: creation of a bi-spline passing through the points of the scan(s) Creating Curves from the Scan (2/2) The default constraint on a split point is "Point", i.e. passage. Click on the green square to change it to "Tangent". A second click will return it to "Point". You can also use the contextual menu of the constraint. Use the contextual menu of the constraint to remove the split point. You can remove the extremity point of a computed curve, and replace it with a new or existing split point.

Copyright DASSAULT SYSTEMES Curve in Space: Used to build a curve using points from existing geometry (usually from the Cloud) Display: Distance between the points and the curve (only in Near Point option).Max value displayed in red. Display of the curvature of the resulting curve. You also access to a new dialog box to adjust the display of the curvature. 3 methods are available: Near Point: Result is a mono arc curve. Smoothing process. Through Points: Result is a bi-spline passing through the points. Control Points: Result is a mono arc curve ( 6 points) built from picked control points. Result is also a multi arc in case of Closed curve option. In case the method used is Near Point, you may control the maximum order of the resulting curve Drawing Characteristic lines on the tessellation

Copyright DASSAULT SYSTEMES Export: This action creates external files from Clouds of Points, Scans or Tessellation Save as Type: Ascii free : point coordinates, Scan delimited by G08 and G09. Cgo: the file created is readable in Catia V4 CGO application. Stl: To create a binary file to the Stl format. Only for Tessellation element. IN ASCII mode, the scans exported have the following delimiters: G08 for the start and G09 for the end. You can export only one element at a time. Therefore, if you want to export several scans, you must use the Grouped into one element option when you create them. You can then use the Import action to recall the file you have created. You can export one element at a time. You may get a STL file through the menu Save As. ! ! ASCII generated by Digitized Shape Editor/CATIA ! ! Begin Scan Delimitor =G08 ! End Scan Delimitor =G09 ! Point Format ='X %f Y %f Z %f' ! ! Total number of scans = 1 ! G08(1) X Y Z X Y Z X Y Z X Y Z X Y Z X Y Z CGO: STL generated by Digitized Shape Editor/CATIA ·` ¿«¿k&¿\¿´CŽ.ÄžoFCLC=¢.ÄÕ˜HC3SCF–.ĘîEC00?ÿ÷ì¿t·¿´Cƒ.ÄËáICãC?­.ĸLCÌC °.ÄøsKC00(§¿®- ¿©¿´Cƒ.ÄËáICÌC °.ÄøsKCLC=¢.ÄÕ˜HC00_°¿ë¿E¿ãC?­.ĸLCxC½.Ä NCÌC °.ÄøsKC00g­¿T¿Òœ¿¢Cú¾.Ä^ºPCNCËÉ.ÄðÇPCxC½.Ä NC00c«¿Œ%¿– Ä NCLC=¢.ÄÕ˜HCÌC °.ÄøsKC0®¿#¿w¿¢Cú¾.Ä^ºPCD+CÓ.Ä1¨S CNCËÉ.ÄðÇPC00H©¿¥(¿¿¢C{Ô.ÄúWC%æCRà.ÄËYC7CºÙ.ÄFVVC00Ȧ¿ï1¿ÃŽ¿¢CôÝ.Äüé[CF–^CHáChé.Äã[C00]©¿Ó(¿T¿¢Cô Ý.Äüé[CHáChé.Äã[C%æCRà.ÄËYC00F²¿¿À ¿ÝCœä.Äj

Copyright DASSAULT SYSTEMES Exercise Presentation And now practice on the 3rd step of the Car Door exercise, to learn about: Creating Scan Section (cut by Planes) on the tessellation Creating curves from the Scan Drawing Characteristic lines on the tessellation Exporting the result Illustration of the exercise step

Copyright DASSAULT SYSTEMES You have seen how to : Draw curves on the points Output result in a neutral format To Sum Up Copyright DASSAULT SYSTEMES 2002 Creating curves 3

Copyright DASSAULT SYSTEMES Advanced lesson Added exercise: Hair Dryer In this lesson you will learn how to recall several Clouds, align them, tessellate them and offset the tessellation Presentation of the exercise : Hairdryer Point Processing Tessellation Offset and export 1/2 Day

Copyright DASSAULT SYSTEMES In this lesson you will learn how to Align several Clouds of Points Point Processing Aligning Point Data Checking results Merging Clouds

Copyright DASSAULT SYSTEMES Align Cloud of Points When the model has been digitized in several steps (eg. presence of undercut area) You need to align the different clouds to work on the entire part. Select the Cloud to move Select the reference Cloud Draw the Area to match on the Cloud to move (you may draw several area), use Valid Trap between each area. Use OK to start drawing the corresponding area on the reference Cloud, and Valid Trap again between each area from the Reference Cloud. Use OK to finish the area input. Answer to the Question. A new Cloud is created. Ergonomic : Do not use automatic move twice for the same alignment. Use it once then optimize by small movements. It is better to use the denser Cloud as the reference Cloud. The result entity has the same structure as the input entity: scans, grids or polygons When using the Automatic move, select areas of uniform size and shapes on both clouds of points When using the Non automatic move, it is better to draw a bigger area for the reference Cloud The output entity is presently a cloud of points, even if the input entity is a cloud made of scans, grids or polygons. The first picked cloud is moved to be fit to the second picked cloud (reference). Then you select a trap of points on each cloud that the system will try to fit. You may select several traps on each Cloud Principle : Aligning Point Data (1/2)

Copyright DASSAULT SYSTEMES Align Clouds using spheres When the model has been digitized in several steps, there may be spheres features to reposition the digits Select the Cloud to move Select the reference Cloud Then pick the spheres on the first cloud, click OK to validate them. If you know the radius of the spheres, check the Constrained check box and enter the radius in the input field. CATIA will compute the spheres with that radius. If you do not know the radius of the spheres, click the first sphere. CATIA will compute this radius and update the input field accordingly. Then you may check the Constrained box and select other spheres that will have the same radius.. Use OK to start picking the corresponding spheres on the reference Cloud, Use OK to compute the alignment. Use the Selective Display option to make the definition of the spheres easier: when this option is active, only the cloud where you should define the spheres is displayed. Once you are finished with the first cloud, it is hidden and the second one is displayed. Ergonomic : While aligning clouds, you can use the function Distance analysis to check the output accuracy. The target will be the output cloud. Since a new output cloud is generated at each alignment, you should repeat the distance analysis with each new output cloud. We recommend that you pick the sphere in a direction orthogonal to the part to process, i.e. along the green axis and not along the black axis in our example. For an easier sphere recognition, we recommend that you pick in the middle of the sphere, not at the edge. The result entity has the same structure as the input entity: scans, grids or polygons. Undo is available on the selection of spheres. The first picked cloud is moved to be fitto the second picked cloud (reference). Then you select a trap of points on each Cloud that the system will try to fit. You may select several traps on each Cloud Principle : Aligning Point Data (2/2)

Copyright DASSAULT SYSTEMES Distance Analysis –1- To compare the distance between Cloud of points or surfaces Click entities from the first set Click entities from the second set - The distance is automatically computed. Each color identifies all discretization points located at a distance between two values, as defined in the Color Scale dialog box. - The element which dimension is the smallest (0 for points,1 for curves, 2 for surfaces for example) is automatically discretized, if needed. -When selecting a set of element, the system compares the greatest dimension of all elements in each set, and discretizes the one with the smallest dimension. -Use the Invert button to invert the computation direction. Ergonomics : Allows you to move the pointer over the discretized element to display more precise distance value between the point below the pointer and the other set of elements. The projection is visualized and the value is displayed in the geometry area. Running Point : Checking results (1/3)

Copyright DASSAULT SYSTEMES Distance Analysis –2- To compare the distance between Cloud of points or surfaces Full: provides a complete analysis based on the chosen color range. This allows you to see exactly how the evolution of the distance is performed on the selected element (default mode). Limited: provides a simplified analysis, but lets you define the tolerance within which the distance deviation should be. For example, for positive values, if the deviation is greater than 0.01, or smaller than -0.01, the points are red, if the deviation ranges between these two values, the points are green. 2 Different modes for display Options : The color scale values as saved when exiting the command, meaning the same values will be set next time you call forth the distance analysis capability. - Right-click a value and choose the Edit contextual menu to display the Edition dialog box. - Enter a new value, to redefine the color scale, and click OK. Allows to display the 2D diagram distance analysis window. The latter allows to visualize the distance evolution. Checking results (2/3)

Copyright DASSAULT SYSTEMES Distance Analysis –3- To compare the distance between Cloud of points or surfaces Normal distance: the distance is computed according to the normal to the other set of elements. Distance in given direction: the distance is computed according to the specified projection direction. Projected distance (between two curves only): the normal distance is computed between the projections of the elements onto a given plane Planar distance: the distance is computed between a curve and the intersection of the plane containing that curve The Projection area helps you define the projection of the vector between the two sets of elements, when the active analysis type is Distance in given direction or Planar distance. The distance analysis can be computed according to the X, Y, or Z axis, or according to the compass current orientation Distance analysis type: Color scale: to display the Color Scale dialog box whether the full or the limited color range Min/Max values: to display the minimum and maximum distance values and locations on the geometry. Points: to see the distance analysis in the shape of points only on the geometry Spikes: to see the distance analysis in the shape of spikes on the geometry.You can further choose to: set a ratio for the spike size choose an automatic optimized spike size (Auto scale) invert the spike visualization on the geometry display the envelope, that is the curve connecting all spikes together Use the Discretization option to reduce or increase the number of points of the second set of elements taken into account when computing the distance. Automatic trap: to delimit the second set of points to be taken into account for the computation, in the case of a large cloud of points, thus improving the performances. Click on more and you get: Checking results (3/3)

Copyright DASSAULT SYSTEMES Merge Clouds As some function operate on mono Cloud of Points, you may have to merge several Clouds of Points into one. Select the Clouds to merge. If you selected a wrong Cloud, it is in your column element to merge, select it and select Remove to remove it from the selection. Use OK to create the new Cloud of Points Ergonomic : A new entity Cloud Union is created Merging clouds

Copyright DASSAULT SYSTEMES Exercise Presentation And now practice on the 1rst step of the Hair Dryer exercise, to learn about: Aligning Point Data Checking results: Distance analysis Merging Clouds Illustration of the exercise step

Copyright DASSAULT SYSTEMES You have seen how to: Align several clouds from different digitization Control the resulting distance Merge several Clouds of Points into one Cloud To Sum Up Copyright DASSAULT SYSTEMES 2002 Aligning cloud of points 1

Copyright DASSAULT SYSTEMES In this lesson you will learn how to tessellate the Clouds of Points Then apply an offset. Tessellation Tessellating the Cloud of Points Offsetting the result

Copyright DASSAULT SYSTEMES Fill Hole Due to an incomplete cloud, you may have to finish tessellation by fillng some small area. Use the function Fill Hole Position the cursor on an edge of a hole: a white triangle is displayed. Click on that triangle to fill the hole. Double-click to exit the action. Ergonomic : Undo is available for this action, but not redo. The holes to fill must be closed. The holes to fill should be small. The centers of gravity of the holes may not be outside the holes. The free edge of a hole may have several loops in it: A computation is first made to create a quadratic shape on top of the hole. Additional vertex may be created before creating the filling facets Tessellating the Cloud of Points (1/2)

Copyright DASSAULT SYSTEMES Flip Edges To better respect the sharp edges, you may have to flip the common diagonal of 2 triangles. Select the Flip Edges icon and a cloud (or an activated portion of the cloud). The dialog box is displayed. Enter the value of Flip Angle, This angle identify the candidate triangles. Click Apply. The edges that could be flipped are highlighted in their eventual new position. Click OK to validate. Ergonomic : You may first activate only part of the tessellation to focus on some area only The systems computes the angles of the normal of each adjacent triangle. Using the Flip Angle value, selects the candidate to the flip action (if angle > Flip Angle ) On these triangles the system flips edges if the computed energy criteria is not reached Tessellating the Cloud of Points (2/2)

Copyright DASSAULT SYSTEMES Offset This operation will create an offset of the selected Tessellation. Create Scans, will allow you to create the free edges of your new tessellation as Scan entities. Free Edges : In this release, a clipping problem may affect the bounding box of the offset tessellation. The offset is computed in the direction of the weighted normals of the points. For better results, you should avoid to enter a high offset value because no control of auto-intersection is performed, no control is performed for disappearing facets neither. Enter the value of the offset. Offset Value : Click Apply to check the Result. Use OK to create the new Tessellation. Offsetting the result

Copyright DASSAULT SYSTEMES Exercise Presentation And now practice on the 2rst step of the Hair Dryer exercise, to learn about: Fill Holes in the Tessellation Flip Edges of facets to better represent the characteristic lines Offset a Tessellation Illustration of the exercise step

Copyright DASSAULT SYSTEMES Copyright DASSAULT SYSTEMES 2002 Tessellation 2 To Sum Up You have seen how to: Fill remaining holes in your tessellation Flip edges to better show characteristic lines Offset a tessellation

Copyright DASSAULT SYSTEMES