"Shrink wrap" an object to remove small cavities

I’d like to print 3D models produced by Altium (Electronics CAD software) - the output is a STEP file of the PCB with component objects placed on it. The bodies of these components often sit slightly proud of the PCB meaning there’s many floating “Blocks” that are only inreconnected by the fine legs of the components . PreForm doens’t seem to recognise these gaps and lets me attempt to print the model. Often this works because the gaps are sufficiently small that the resin manages to solidify in these gaps, but it’s not guaranteed.

I’ve been trying to use SolidWorks to “wrap” the object - like the inside skin of a mold, which SolidWorks can do for single parts, but not for assemblies. My local SolidWorks support vendor can’t come up with any solution to “shrink wrap” a model so that all minor/directional cavities woud be filled-in by an outer shell/skin.

If SolidWorks is no use, what else can I look at? This is a regular workflow for me, so hand-editing dozens/hundreds of components each time I want to print isn’t really viable - I want some automated solution.

Try Meshmixer. I’m pretty sure it has a “shrink wrap” function. You may need to output the model as a DXF to use it, though…

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Meshmixer work fine to wrap an object in order to create a solid, but it’s not without drawbacks.

For one, if you want to get the shape accurate, you will need to increase the number of polygons, doing that can result in a model that has millions of polygons.

I have an alternate solution. Save you model in Solidworks as STL, and import it into Meshmixer. In Meshmixer, duplicate your model, then offset it vertically just enough to fill the gap under the IC components.

Here is a quick and dirty example:

At this stage your model will have both parts overlapping each other, and together they would be a little taller than the original (vertical accuracy will be off slightly).

If you don’t mind that, just combine the 2 parts and export them as STL for printing.

If on the other thing you want to fix the vertical inaccuracy, Use the plane cut function to remove the same amount you offset the part by, from the bottom

When done, export the part back to STL and print it.

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clever, @Dudemeister !

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