VXmodel 3D Scan-to-3D Print Topo Map Tutorial

Objective: Create a manifold and aligned mesh from a 3D scan for 3D printing.

1. Open VX Elements to the main screen. Choose the VXmodel module, and click Browse

2. Navigate to your STL file, choose it, and click Open. Ensure your import units are the same as what the mesh was saved.

3. You should see your imported mesh in the 3D view, and the VXmodel toolbar appear.
4. To review the VXmodel toolbar:

Add Entity (Red) – generates 3D and 2D IGES/STEP features which may be imported into a modelign software to construct a 3D model

Auto Surface/Single Patch Surface (Green) – create a nurbs surface wrap over the entire mesh, or generate a single surface patch on a single surface of the mesh

Align (Blue) – tools to align meshes to global coordinate system, or to additional meshes

Delete/Copy/Cut (Orange) selected mesh triangles

Clean Mesh (Purple) – automatically analyzed and improves mesh for surfacing and 3D printing

Improve (Brown) – individual tools for improving the mesh surface for surfacing and 3D printing

Edit (Pink) – tools to alter and edit the mesh

Compare/Combine/Merge (Yellow) multiple meshes

Transfer (White) – automatically export and send model features directly to SolidWorks, Inventor, or Solid Edge

Mesh/Trangle Selection Tools (Black)

5. Orient the Mesh to bring it to the center of the 3D viewer.

• Note: If the screen seems to orient around a point far away from the mesh, change this by uing Right Mouse Click in the 3D view space, select Set Rotation Center, and left click on the mesh.

6. Click the Clean Mesh tool. VXmodel will automatically analyze and select the initial problem areas of the mesh.  Click Apply to fix these areas.  Once complete, and the number of problem areas will be zero (or minimized.)  Click OK to exit.

7. For this part, the goal is to create a completely watertight (manifold) mesh for 3D printing. Notice we must fill a few small holes throughout the mesh, as well as cap the bottom of the mesh.

8. Choose the Fill Holes tool

9. For this particular model, we have 3 holes remaining in the mesh that the automatic Clean Mesh tool did not fill. One of these holes is the bottom void, which we will not yet worry about.  The other two are small, and highlighted by the pink boundary as seen below:

10. Under the Fill Hole Mode, choose the Whole option, and select Curvature for method. We want to fill all but the largest hole in this example, so slide the Selected Boundaries bar to fill holes 2 of 3 (the largest hole will always be the last).  The boundaries to be filled will change from pink to orange

11. Click Apply to fill, then OK to accept and exit the Fill Holes Command.

• Note: If an error appears that an individual hole cannot be filled, you may have to use the Defeature tool.  This works by selecting the surrounding triangles, which are used to remove a feature (or hole) within the selection.

12. We must now create a flat bottom for our part.
13. Create a Plane from the Add Entity menu, the Building Mode should be set to Triangle Selection, and choose the selection tool to be Boundary Selection.

14. Click on the pink boundary around the bottom of the part to apply a best fit plane across this boundary, then click Create. Then click Close to exit the Plane tool.
15. The bottom boundary is very rough and would create an unsatisfactory hole fill to cap off our part. We will use the Plane 1 created above to cut our mesh and create a cleaner boundary.

16. Use the Cut Mesh tool under the Edit group, select Plane 1, and offset it 1″ into the mesh.

• Note: You can also freely drag the cut plane to a desired location by clicking and dragging the blue arrow on the plane.

17. Click Preview. The mesh portion to be left remaining is colored blue, and the portion to be removed will be grey.  In this instance, the software will cut the mesh in an undesired direction.  Click the Flip Plane button to flip the cutting direction to trim of the bottom of out mesh, and leave the top.

• Note: When the plane is flipped, the blue arrow will flip directions.  Whichever direction it is facing, THAT portion of the mesh will remain after the cut, even if the color does not update to reflect the new kept portion as blue and the cut away as grey.

18. If the thickness of the part at this cut location will work for 3D printing, click the Fill Cut Plane check box. This will cap the mesh with a flat bottom at this cut location, and you can skip ahead to Step 27.  If the thickness must remain the same as the originally scanned part, leave this box unchecked and proceed.

19. You should now have a much cleaner boundary. In this example, the foam did not provide a super clean scan, and the boundary is still a little rough.  To really flatten it out to make the extrusion in the following step much cleaner, click the Edit Boundary tool under the Improve group.

20. Left click on the bottom boundary, and set the Curve Tension option to 2. Then click Apply to set the changes to the boundary, and OK to exit the tool.

• Note: Be careful to set the Curve Tension to an appropriate value for each situation.  This option effectively pulls the boundary tighter, and therefore smoother.  In this example, we want to smooth the boundary as much as possible without rounding the sharp corners of the bas.  Too much tension will round these more than desired, and too little will not smooth the boundary enough.  Verify your settings by zooming in and inspecting the preview.  The original boundary will be orange, and the previewed new boundary will be green.  The results achieved below look good.

21. We will now extrude the boundary past Plane 1, then use the plane to split and cap the mesh. Choose the Extrude Boundary tool under the Edit group.

22. Click the boundary, choose Plane 1 for the plane (this will be the extrusion direction and length) and offset it downward slightly (1/4″ works well in this case) to bring the mesh past the Plane 1 location. Be sure to un-check “Fill Boundary”.

23. Click Apply to create the Extrusion, then OK.

24. It’s now time to split the mesh and cap the end. Again we will choose the Cut Mesh tool under the Edit group.  Choose Plane 1 with an offset of 0″ and the Fill Cut Plane option checked. Flip the Plane 1 direction to ensure the arrow is pointing toward the top of the part.  Then click Preview.

25. You should see the top of the mesh remaining and capped, and the small 1/4″ portion to be removed as grey. Click OK.

26. By hiding Plane 1 (use the eyeball symbol next to Plane 1 in the Navigation Tree) we can see the bottom is properly capped.

• Note: if the bottom failed to cap, try the Cut Mesh tool again, and very slightly offset the cut plane in one direction or the other.  This usually solves the problem.

27. Run the Fill Holes and the Clean Mesh tools once more to ensure we have a cleaned and manifold mesh after our editing procedures.
28. We are now ready to align the mesh to the Global Coordinate system. This will be done with a 3-2-1 (Plane-Line-Point) alignment.
29. Plane 1 is already in place, so we will create a few features to generate a line and a point on the edge and corner of our mesh.
30. Choose the Plane tool. The Building Mode should default to Triangle Selection and the selection tool to Similar Normal.  Hold CTRL and left click the  flat extruded portion of the sidewall shown.  A plane will be best fit to this portion of the mesh.  Click Create to apply the plane.

31. Without exiting the Plane tool, repeat the previous step by choosing the next side shown below and click Create. Then click Close to exit the Plane tool.

32. We will now create a line at the intersection of Plane 1 and Plane 2. Choose the Line tool, change the Building Mode to Two-Plane Intersection, then choose Planes 1 and 2 from the list.  Click Create and then Close.  A vector should appear along the edge of the scan.

33. Our final entity will be a Point at the intersections of Planes 1, 2, & 3. Choose Point, select Three-Plane Intersection for Building Mode, and select Planes 1, 2, & 3 from the list.  Click Create an then Close.  A point should appear at the corner of the mesh.

34. We now have 3 features for an alignment. Select the Align to Origin tool from the Alignment group.
35. We want the Z-axis to be coming up from the topographic surface of the part, the Y-axis running down the long side of the part, and the Origin at the corner. To do this, follow the steps below:

1. Choose the Constraint as Plane XY (will place Z in proper axis) and Entity as Plane 1. You must use the Flip Normal button next to your Plane 1 selection to properly align the part in the positive direction.
2. Choose the next Constraint as Axis Y and the Entity as Line 1.

3. Choose the final Constraint as Origin Y, and select Point 1 as the entity.

4. If happy with result, click Align. We now have a manifold and aligned mesh ready for 3D printing.

36. All created entities may be removed from the workspace if desired by right clicking on them in the Navigation Tree and selecting Delete.
37. To export the mesh for printing, Right Click the mesh in the tree and choose Export (Or navigate to File=>Export=>Mesh).
38. This concludes the Scan-to-Print Topo Map Tutorial.