While many examples exist of impressive texturing done on 3D printed Stratasys PolyJet printed parts (some wild examples are here), I have to admit it took me a while to learn that true texturing can also be added to Stratasys Fused Deposition Modeling (FDM) parts. This blog post will walk you through adding texture to all faces or some faces of a solid model, ready for FDM printing. You, too, may be surprised by the results.
I know that complex texturing is possible in a graphics sense with such software packages as Rhino, PhotoShop, Blender and more, but I’m going to show you what you can achieve simply by working with SolidWorks, from Rev. 2019 onwards, as an easy starting point. From there, you can follow the same basic steps but import your own texture files.
SolidWorks Texture Options
First off, let’s clarify some terms. Texture mapping has existed for years and strictly speaking creates a 2D “texture” or pattern. If I were to wrap that imagery around a 3D CAD model and print it on, say, a PolyJet multi-color 3D printer, I’d get a 3D part with a flat or perhaps curved surface decorated with a multi-color “picture” such as a map or a photo of leather. It could conform, but it’s still basically a decal.
A 3D texture instead is more properly referred to as Bump Mapping (not to be confused with …..too late….bit mapping). Bump mapping interprets the color/contrast information of a 2D image such that it renders light and shadow to give the illusion of a 3D part, while remaining in 2D. Taking this concept one step further, 3D CAD software such as SolidWorks can apply rules that convert white, black and grey shades into physical displacements, producing a kind of tessellated topology mapping. This new information can be saved as an STL file and generate a 3D printed part that has physical, tactile variations in material height across its surface. (For a detailed explanation and examples of texture versus bump-mapping, see the GrabCAD Tutorial “Adding Texture to 3D Models.”)
For FDM parts, you’ll get physical changes on the outer surface of the part that appear as your choice of say, a checkerboard, an arrangement of stars, a pebbly look or a series of waves. In the CAD software, you have a number of options for editing that bump map to produce bigger or smaller, higher or lower, finer or coarser variations of the original pattern, prior to saving the model file as an STL file.
Stepping through SolidWorks 3D Texturing
The key to making this option work in SolidWorks 3D CAD software (I’m using SolidWorks 2020), is in the Appearances tab. Here are the steps I’ve taken, highlighting the variety of choices you can make. My example is the Post-It Note holder I described in my PADT blog post about advanced infill options in GrabCAD Print.
- Open Post-It note CAD file, select Solid Bodies (left menu) and select Appearances (in the right toolbar).
- Expand Appearances and go all the way down to Miscellaneous, then click to open the 3D Textures folder.
- Scroll down to choose one of the more than 50 (currently) available patterns. Here, I’ve chosen a 5-pointed star pattern.
- I dragged and dropped that pattern onto the part body. A window opens up with several choices: the default is to apply the pattern to all faces:
However, you can mouse over within that pop-window to select only a single face, like this:
- When you’ve applied the pattern to either all faces or just one or two, you’ll see a new entry in the left window, Appearances, with the subheading: 5-pointed Star. Right-click on those words, and choose Edit Appearance:
Then the Appearances window expands as follows, opening by default to the Color/Image tab:
In this pane, if desired, you could even Browse to switch to a different pattern you have imported in a separate file.
- Click on Mapping, and you’ll see a number of “thumb wheel” sliders for resizing the pattern either via the wheel, clicking the up/down arrows, or just entering a value.
Mapping: this moves the pattern – you can see it march left or right, up or down. I used it to center the stars so there aren’t any half-stars cut off at the edge.
Size/Orientation: You can also try “Fit width to selection” or “Fit height to selection,” or experiment with height and width yourself, and even tilt the pattern at an angle. (If you don’t like the results, click on Reset Scale.) Here, I’ve worked with it to have two rows of five stars.
- Remember I said that you can also make the pattern higher or lower, like a change in elevation, so that it stands out a little or a lot. To make those choices, go to the Solid Bodies line in the Feature Manager tree, expand it, and click on the part name (mine is Champfer2).
In the fly-out window that appears, click on the third icon in the top row, “3D Texture.” This opens up an expanded window where you can refine the number of triangular facets that make up the shape of the selected texture pattern. In case you are working with more than one face and/or different patterns on each face, you would check the box under Texture Settings for each face when you want to edit it.
Here is where you can flip the pattern to extend outwards, or be recessed inwards, or, if you brought in a black/white 2D pattern in the first place, you can use this to convert it to a true 3D texture.
I’ll show you some variations of offset distance, refinement and element size, with exaggerated results, so you can see some of the possible effects:
In this first example, the only change I made from the default was to increase the Texture Offset Distance from 0.010 to 0.200. The stars are extending out quite visibly.
Next, I changed Texture Refinement from 0% to 66.7%, and now you can see the stars more distinctly, with better defined edges:
Finally, I am going to change the Element size from 0.128 to 0.180in. It made the star edges only slightly sharper, though at the expense of increasing the number of facets from about 24,000 to 26,000; for large parts and highly detailed texturing, the increased file size could slow down slicing time.
- To make sure these textured areas print, you have to do one more special step: Convert to Mesh Body. Do this in the Feature Manager by right-clicking on the body, and selecting the second icon in the top row, “Convert to Mesh Body.” You can adjust some of these parameters, too, but I accepted the defaults.
- Lastly, Save the file in STL format, as usual.
You can definitely see the stars popping out on the front face; too bad you can also see two weird spikes part-way up, that are small bits of a partial row of stars. That means I should have split the face before I applied the texture, so that the upper portion was left plain. Well, next time.
Here’s the finished part, with its little spikes:
And here’s another example I did when I was first trying out a checkerboard pattern; I applied the texture to all faces, so it came out a bit interesting with the checkerboard on the top and bottom, too. Again, next time, I would be more selective to split up the model.
NOTE: It’s clear that texturing works much better on vertical faces than horizontal, due to the nature of the FDM layering process – just be sure to orient your parts to allow for this.
For More Information on Texturing
SolidWorks offers a number of tutorials on the texturing set-up process, such as http://help.solidworks.com/2019/english/solidworks/sldworks/c_3d_textures.htm, and Shuvom Ghose at GrabCAD gives even more details about what to expect with this process in his post https://grabcad.com/tutorials/how-to-3d-texture-your-parts-for-fdm-printing-using-solidworks-2019
There will also be a general Stratasys webinar on The Benefits of 3D Printing Physical Textures on July 29 at 9am PT.
Commercial aircraft companies are already adding a pebble texture to flight-approved cosmetic FDM parts, such as covers for brackets and switches that keep them from being bumped. If you try this out, let us know what texture you chose and send us a photo of your part.
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