Best Practices for Working in KeyShot & GrabCAD Print

Stratasys

30 Nov, 2020 07:56 PM

KeyShot 3D rendering software from Luxion Inc now seamlessly integrates with GrabCAD Print for a smooth and quick export of 3MF files. This new workflow allows designers to easily export 3MF files (that maintain color and texture data) from KeyShot into GrabCAD Print.

In this tutorial guide, we’ll discuss best practices for when you’re working with KeyShot and GrabCAD Print.

1. Step 1: Working with Material Properties

   Certain material properties work better than others when exported from KeyShot into GrabCAD Print. For instance, the following material properties come out wonderfully on our J55 Stratasys 3D printer:

   • Paint
   • Plastic
   • Textures
   • Metal
   • Transparencies
   • Labels
   • Gradients
   • Displacement
   • Bump
   • Wood
   • Stone
   • Fabric

   

   
   

   The following material properties can produce unpredictable results, so we don’t recommend applying: 

   • Fuzz (Too fragile when printing and post-processing)
   • Sub-surface
   • Reflective (Highly dependent on materials loaded and post-processing)
   • Light (This only matters when rendering)
   • Real metal (This depends on the material loaded. The closest you can get is interacting with our digital materials)
   • Soft (Depends greatly on how you customize the shore value in GrabCAD Print)
   • X-Ray (Requires actual MRI or CT scans)
   • Cutaway ( Can bring file into SOLIDWORKS then split)

   

   
   

   
   

2. Step 2: Working with labels

   In our Working with Labels tutorial, you’ll see just how easy it is to apply labels in KeyShot. However, one of the biggest mistakes you can make is leaving the “Projecting labels” default setting on. 

   Projecting labels with the default settings can result in a model that renders well, but has a mirrored label on its back side (that you can’t see on a 2D render). 

   When 3D printing, all aspects of the design become visible once you actually hold the model. See the image below.

   

   
   

   To prevent this, try either of these two options:

   • Option 1: Uncheck “Two Sided”, Use the “Depth” parameter (When using the default planar projection)
   • Option 2: Split the face of the label (either in Keyshot or in the modeling software) and apply the label only to that face

   In addition, we also suggest using high resolution labels, as low resolution can appear differently 3D printed. See image below.

   

   Some other quick tips for working with labels:

   • Use 300DPI+ resolution labels and textures, zoom in to make sure it looks sharp enough before export. Export as >600dpi.
   • Also don’t forget to set the background color or you don’t get the white glow around the transparent graphics.
   • Don’t use extra surfaces for labels. Just put the labels on directly.

   
   

3. Step 3: Working with Bump Maps

   Loading a bump map into GrabCAD Print will displace the surface during printing; the visualization will be just for the bump map, and won't show any overlaps. 

   To prevent this: Make sure there is enough tolerance for the displacement to occur. Tolerance should always be greater than the displacement height.

   (Reading bump map is not yet included in GrabCAD Print but will be coming in future versions).

   

   
   

   
   

   

   
   

4. Step 4: Working with Thin Bodies

   When adjacent bodies thinner than 2mm each have different colors, their colors will not be accurate. This is because the colors need a 1mm thickness plus a white core behind them to appear bright and accurate, and layering multiple thin colors on top of each other will hurt the color.

   Tip: When shells thinner than 2mm are touching and are different colors – combine them before going into KeyShot to end up with one shell. Then paint the faces on the surface.

   

   
   

   
   

   
   

5. Step 5: Managing “Smooth” Expectations

   Smoothing shaders applied in KeyShot do not actually tessellate or add any polygons to the model. If the model does not have enough polygons for its size, it can appear low-res in the actual print.

   Tip: Make sure the model has high enough resolution for print: 

   • Load it into GrabCAD Print to see the real triangle view without smoothing to verify. 
   • Use PJ Printing Best Practices
   • Review KeyShot materials tips

   
   

   

   
   

   
   

6. Step 6: Working with transparency in GrabCAD Print

   In GrabCAD Print, assign material core to “Same Material” when using transparency. Selecting “Same Material” on the advanced color settings will apply the core color and transparency to be the same as the coating. This results in a more realistic solid glass/plastic appearance. 

   Remember, the thicker the part, the darker and more saturated it is.

   

   
   

   Another tip: Using Glass/Solid Glass/Gem/Liquid/Dielectric + #FFFFFF color will export a fully transparent part.

   

   
   

   

   Avoid using the material types, as they are not support by GrabCAD Print yet, and may result in unexpected results:

   • Translucent Medium
   • Scattering Medium
   • Diffuse/Specular/Transmission of “Plastic (Transparent)”

   
   

   

   
   

   
   

7. Step 7: Working with the correct units, dimensions, & dpi

   400dpi on 10mm cube vs 400dpi on 10meters cube makes a big difference in file size and exporting time. Some file types going into KeyShot will not contain units, and could lead to exporting the wrong size, impacting export time -- not to mention possibly crashing KeyShot.

   Tip: Make sure the units are set correctly on export from the Modeling software, import into Keyshot, and when exporting from KeyShot.

   

   Other tips to consider when you’re working in GrabCAD Print:

   

   
   

   • 400-600dpi (always good to have more dpi than the printer). The default should be 400 at the moment unless it’s changed by the user.
   • Keep the default number of samples (16)
   • Check “Prefer Textures” in KeyShot. Currently, it’s not the default. If you pick “Geometry Nodes,” it will export the displacement as tessellated polygons, so the export will take longer and the file size will be larger. Use it only if you need it; in a few versions from now, GrabCAD Print will displace from the bump map, so you can still export quickly AND have your surface finish too.
   • Remove the last checkbox for “Use Calculated Depth.” When it’s on, it will apply the color on transparent parts according to the thickness on each polygon. It simulates transparency thickness when the core is clear.

   
   

   Next year in GrabCAD Print, the core will be set to the same material and not clear so it won’t need to be simulated, and the thickness will actually change the appearance like in the render. Removing this will make the export a lot faster.

8. Step 8: In summary

   The new integration between KeyShot and GrabCAD Print will help designers bring their parts to print faster. Just remember the following tips and your prints will come out as you expected!

   1. Project labels on the intended face only (split, 1-side). Remember, real life 3D reveals the back side too.
   2. Use procedural textures or hi-res textures. 
   3. Don’t forget displacement changes the physical model.
   4. Don’t use extra surfaces just for labels – just put labels on directly.
   5. Merging (combine add) thin bodies so colors don’t change.
   6. Low-Poly models may appear smooth in KeyShot render but will actually print Low-Poly
   7. Autofix before printing; some models might have reversed polygons and open faces. Use the GrabCAD Print Auto Fix feature to get the best print.
   8. Assign material core to “Same Material” when using transparency to simulate “Solid Glass” and similar
   9. Make sure to use the correct units and dimensions. If the model is too big, baking it might take very long.
   10. For 100% transparency the best material to use is “Glass” with #ffffff color.

   
   

   For more tips on working in KeyShot, check out their tutorials!