Creating Smart Models From Scan Data

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Charla Ball
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1 Rapidform Tech Tip Creating Smart Models From Scan Data Related Product Version Rapidform XOR3 Goal To create a smart model from scan data. A smart model is a parametric model that uses parameters intelligently to control the design of the model. This concept is used when designing a part that needs to change to fit a number of similar parts in a family. One example is a light switch cover. How many switches can it cover? If the model is designed well, you can make a small change to it to adapt it quickly and easily to cover any switch. Change one dimension, get a totally new model. Instead of changing several dimensions to create a new version of a part, many different parameters can be linked to a few key parameters. This is how a model becomes smart. Changing several dimensions to achieve a goal is always possible, but may take a considerable more amount of time. This is why it is efficient to build models that allow for easy modifications. This tech tip will guide you how to use XOR to create intelligent models. How much of this can be done in XOR? XOR supports many ways to make intelligent models. Some specific tools are: Convert Entities in 2D sketching Copies geometry into a sketch, linking the 2D and source geometry Pierce Constraint in 2D sketching The Pierce Constraint is specifically designed to control 2D sketches based on pre-existing geometry outside of a sketch plane Pierce links a point or end-point to a sketch entity or edge of a model Points must exist at an intersection of parent geometry and a sketch plane Pierce allows the movement of points that always follows their parent

This concept is used when designing a part that needs to change to fit a number of similar parts in a family. One example is a light switch cover. How many switches can it cover?

2 Up To Vertex, Up To Surface, and Up To Body in Extrude In the Extrude command, a distance can be set using the Up To Vertex, Up To Surface, or Up To Body methods. These options link results to other geometry instead of a static value These options allow an extrude depth to change if the parent geometry changes. What else can be done in my native CAD software? Due to limitations in compatibility between CAD software, some constraints cannot be transfered using LiveTransfer into native CAD automatically. Converted entities and the Pierce Constraint are especially affected by this, so they must be re-created using the tools in the target CAD system. CAD systems usually have more advanced capabilities to further define a model intelligently. Some of these tools include: Formulas as Dimension values Users can specify a dimension as a function of another dimension, such as: Dim2 = Dim1/3 (Dim2 will always be 33.3% of Dim1) Dimension values as Variables Multiple dimensions can be defined to have the same value by using a variable. If this variable is changed, all linked dimensions will change. Radius-difference dimensions Most CAD software usually suports creating a dimension between two concentric circles, and the dimension created is the difference between the radii (Rad1-Rad2). This is helpful for cases where concentric circles should be linked and the secondary radius is just an offset from a base circle. Example: 2 Scan data provided by Artec Group (

Due to limitations in compatibility between CAD software, some constraints cannot be transfered using LiveTransfer into native CAD automatically.

3 Method Let s make a model of the plastic cover that could adapt to different components in an assembly. We don t know what part goes inside of the cover, but we can make some guesses based on what we see. The component that fits inside is round and would be concentric with the cover. If the design or size of the component changes, the design of the cover will need to be changed to match it. What are the driving parameters of this cover? Thickness - 2mm This is a thin plastic molded part Maintaining a mostly consistent wall thickness is key to manufacturability Overall Diameter - 59mm The outer diameter should control the fins, bosses, and opening The inner diameter is ideally some fraction of the outer diameter 1. First, Create a Master Sketch. This master sketch will control all child features and will be the sketch that will be modified to create a new part. 2. The radius of the circles can be linked by using a Construction line. Drawing a horizontal line with each end point Coincident on each circle will allow the length of the sketch to be defined if one circle diameter is defined. This step links the second circle to the first. 3

If the design or size of the component changes, the design of the cover will need to be changed to match it. What are the driving parameters of this cover?

4 3. In XOR two main dimensions need to exist: The Outer Radius, and the Inner Radius. To control the size of the hinge opening, draw two lines that are Coincident with a reference circle, and Concentric to all other circles. 4. Link other sketches to the Master Sketch using the Pierce Constraint and use the Convert Entities command to us use the diameters from the Master Sketch. The easiest way to do this is to draw vertical construction lines, making sure one end is coincident with a corner or endpoint, while using the pierce constraint on the other end to link it to the Master Sketch. Double click on an end point to open the constraint manager, and hold CTRL or SHIFT and select a circle from the Master Sketch. Select the Pierce constraint to add it. 5. Model the rest of the part. Fully defining each sketch will help to fully define sketches that have all degrees of freedom constrained. This is accomplished using geometric constraints and dimensions. The position of the sketch in the X and Y directions must also be defined. Now the model is prepared for changes in dimensions. The better defined the sketches are, the less likely that they will behave unexpectedly. The larger the change introduced, the higher the likelihood of a sketch failure. When an entity is fully defined, it will turn black. Over-defined entities and constraints will be shown in red. 4

Link other sketches to the Master Sketch using the Pierce Constraint and use the Convert Entities command to us use the diameters from the Master Sketch.

5 6. Use the Convert Entities tool to link the sketch to the existing solid body. Edges can be converted to re-use in sketches, and as the model updates these lines and arcs will update as well. 7. Use the Extrude command to make a cut out of the neck and hinge of the part, using the Up To Surface method which will choose where the Extrude will stop. Be sure to select a face that has a connection to the Master Sketch. Now when the Master Sketch changes, the extrusion distance will update automatically 8. Use the Hollow command to create the other side. Model the part as a large solid and select the faces to remove, setting the thickness as 2mm. Any changes made before this feature will update the Hollow, and the shape will maintain a 2mm thickness. 5

Use the Extrude command to make a cut out of the neck and hinge of the part, using the Up To Surface method which will choose where the Extrude will stop.

9. Model a single straight rib and pattern it using the Circular Pattern command and set 12 instances but use the Skip Instances option to skip the unwanted ribs. 10.

6 9. Model a single straight rib and pattern it using the Circular Pattern command and set 12 instances but use the Skip Instances option to skip the unwanted ribs. 10. Use the Convert Entities command to make bosses easy to place. The center points of the circles and the cross shaped box should be coincident with a concentric construction circle from the Master Sketch. Use a construction line to define the offset value and the bosses will now move with the outer diameter. 6

The center points of the circles and the cross shaped box should be coincident with a concentric construction circle

7 11. Add Drafts to vertical faces. If the part was manufactured, drafts would be necessary because truly vertical walls cannot be easily removed from molds due to friction. It is typical to add a nominal draft, usually 1 degree. This ensures that the part is ready for manufacturing. 12. The intelligent model is now ready. Use the complete XOR file for this part found at: to change the main diameter, watch the model rebuild, and change dimensions once a failure is caused to overcome and fix the failure. The LiveTransfer results for each CAD system can also be downloaded. Some additional work has been done in the native CAD files to complete the smart models. 7 Rapidform, Rapidform XOR, XOR, Rapidform XOV, XOV, Rapidform XOS, XOS, InspectWorks, Rapidform.dll, Rapidform DENTAL, Rapidform SURVEY, and the company logo and all product logos are either registered trademarks or trademarks of 3D Systems Korea, Inc. All other trademarks within this user guide & tutorial are the property of their respective owners and are used for identification purposes only. Other than to identify this Software and publication, individuals or organization purchasing the software are not entitled to use 3D Systems Korea s trademarks without 3D Systems Korea s prior written consent. Copyright 3D Systems Corporation. All rights reserved.

Use the complete XOR file for this part found at: to change the main diameter, watch the model rebuild, and change dimensions once a failure is caused to overcome and fix the failure.

SOLIDWORKS: SKETCH RELATIONS

SOLIDWORKS: SKETCH RELATIONS Sketch Feature: The shape or topology of the initial sketch or model is important, but exact geometry and dimensions of the initial sketched shapes are NOT. It recommended to work in the following order: