HelpTutorialsviaCad Tutorial

viaCad Tutorial

Tutorial by Shapeways community member: Will Culpepper (willc2)

Product overview

ViaCAD is a 3D Parametric Solid Modeler comparable to Ashlar-Vellum Cobalt or IMSI/Design TurboCAD. The version used is ViaCAD 2D/3D v6, which is aimed at the consumer market with a price of $99. It is cross-platform and has an upgrade path to more full-featured products in the Punch! CAD product line. It offers fine control over exporting STL meshes for use at Shapeways.

For more information, go to the Punch! Software website. They have discussion forums and you can download a free trial version to follow along with this tutorial.

Tutorial overview

In this tutorial you will be shown the steps to build a simple object in viaCAD, apply rounding to the edges and hollow out the interior. Then how to convert the resulting model to an STL-formatted polygonal mesh, suitable for upload to Shapeways.

Here is the viaCAD interface:

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Note: All values will be in Inches and US dollars.

Summary:
Step 1: create an object
Step 2: add rounding to the sharp edges
Step 3: hollow out the object
Step 4: add a hole to the hollow object
Step 5: Determine the volume of your object to calculate the price
Step 6: Rotate the model for a good preview image
Step 7: Export the model as STL
Step 8: Tuning Mesh Parameters for proper STL output
Step 9: Upload the file to Shapeways.com

Step 1: create an object

Start by creating a cube with the Block Tool.

Select the Block One-Point Tool. This will allow one-click creation of a cube centered at the origin point.

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Enter a length, width and height of 1.0 and click at the origin point. A cube is created.

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Step 2: add rounding to the sharp edges

Select the Blend Edge Tool

Choose the Constant Blend Tool and set the option menu to Radial.

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Enter a Radius of 0.050 and leave the Setback value at 0.0 Drag-select to round the whole cube at once.

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Step 3: hollow out the object

Select the Shell Feature Tool. It is located on the same tool bar shelf as the Constant Blend Tool. Hold down the mouse and more tool icons will appear.

Enter an Offset value of 0.10

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Click the object to choose it for shelling. Click anywhere outside the object to complete the shelling feature. The object becomes hollow. You can verify this by turning the object transparent. Right-click on the object and a popup menu appears; select Transparency.

The object now becomes transparent.

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Step 4: add a hole to the hollow object

It is not enough that the object be hollow. It should have some kind of hole so that at printing time, the supporting material can be removed. Some supporting materials expand after printing and may burst open the model if the walls are not thick enough. Choose the Simple Hole Tool. It is located on the same toolbar shelf as the Constant Blend Tool.

Choose the First Blind and Normal popup menu options.

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Enter a Diameter of 0.10 the other values are ignored. Choose the bottom face of the cube to place the hole.

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Just click YES.

then the hole is created.

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Step 5: determine the volume of your object to calculate the price

Make sure the object is selected and choose MENU--->VERIFY--->VOLUME...

The volume of the object will appear.

Multiply the volume by $30 to get the approximate cost for White Strong & Flexible material. The current prices can be found here. If you are working in centimeters, multiply the volume by $1.87 for WSF material. Click the OK button to close the Verify volume window.

Step 6: rotate the model for a good preview image

Another model is used to show this because our cube is too symmetrical. If your model looks like this in viaCAD

It will look like this when you import the object into Shapeways.

To correct that, rotate the object -90° on the X axis before exporting. Select the Rotate Tool. It’s located on the same toolbar shelf as the Translate Tool.

Choose the X-axis on the option menu and set the Angle to -90° (that’s negative ninety degrees).

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Select the object, and then click the mouse to pick a point to rotate around, like the base of the object.

The object rotates. It should look like it fell backwards.

When we bring the object into Shapeways, it will look correctly oriented. Now we go back to our original cube.

Step 7: export the model as STL

Start by zooming in on the model and panning a little to the side. This is so you can see the preview mesh while changing the STL export settings.

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Select the model and choose MENU--->FILE--->EXPORT...

Choose STL from the Export Type list.

Choose the Binary option, which reduces the file size. Choose the Selected Only option. This is to keep from accidentally exporting construction objects or hidden geometry. Click on the OK button. Choose a name and location to save the STL file and click the Save button

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This will bring up the Mesh Parameters dialog box where you can control how the facets of the STL file are configured.

In the modeling window you can see your object divided into facets.  Notice how curved areas have tiny facets while flat areas have large ones.

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Click on the Update button to see how many facets these settings will produce. Note: A simple cube would have about 12 facets but our cube has rounded edges. Rounded features require more facets to look smooth but the viaCAD defaults are normally set too fine for general use. This rounded cube model is about 5000 facets and therefore under the Shapeways limit of 100k, but in the next step it is shown how to tune the Mesh Parameters for other objects.

Step 8: tuning mesh parameters for proper STL output

The first setting to change from the defaults is STL Facets. This turns all facets into 3-sided polygons, a.k.a. triangles. This setting will actually increase the total facets, but it is used because legal STL files should only contain triangles.

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The second setting to change is the Normal Deviation value. Increase it to 12 and rounded features will use fewer facets.

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Do not raise it too high or your model will print with faceted planes like a gemstone. Also, detailed features may become distorted.

Notice how the flat sides of the model now have long skinny triangles? If they are too skinny it can cause errors on more complicated models. To break them up, change the Edge Length value. Start at a value like 1.0 (inches), update the preview and slowly back it down in 0.3 increments. If you set the value too small, it will create huge numbers of facets and use up all your computer memory, causing a crash.

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For a simple model like this, here are some good settings:
STL Facets = ON
Normal Deviation = 12
Edge Length = 0.3

Leave the other settings as is. This should create a model with about 5000 triangular facets. Click the OK button to accept these settings and the exporter will create an STL file.

Step 9: upload the file to Shapeways.com

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Go to the my designs page. Click the Upload button. Choose the file to upload. Set scale to Inches (if that's what you used). Enter a Title, Category and Model View Status. Click the Upload button. After the model is processed, view it in the gallery and order a 3D print. Good Luck!

If you have any questions, ask them in the forum, so everyone can share information.

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