Foam Cut-out

I am totally new to sketchup. I have a specific need in mind. I am able to work around CADs. Is there an “easy” way to invert a selection? That is if I import a CAD file Sketchup of VWX (or similar), I am trying to make a foam cutout for a case insert. So, I need the opposite selection. If I make a foam box, I need to have the item work as an outline for the sutter. Not really sure what the best way to do this would be. Any suggestions?

If I import a CAD for “The thing”. I need to “Thing” to sit cradled in a foam cutout of the 3D outline of the “thing”. How would I go about doing that?


Yes. You should be able to do that using the Subtract tool in the Solid Tools set. (Your profile indicates you are using SketchUp 2019 which is only available as the Pro version and includes the Solid Tools.)

The shape you use for cutting out the foam needs to be a solid as does the foam. There are also more manual ways to do this using Intersect Faces and other tools.

Here’s a quickie example. In this case I only want the recess for the body of the jack so I made a version of it with no hole down the middle. It’s a solid component as is the block of “foam”. Use Subtract or Trim from the Solid Tools created the recess.

As a new SketchUp user, though, you’ll need to get to grips with the fundamentals of the native tools. You should start doing that here.


Not sure if you literally want VWX, but if so you can draw the outline of your foam shape around the letters and extrude the outer ( non letter ) part.
SU will often not create faces as expected ( you see when i first attempt a selection the letters are not separate) so you will have to trace a part of the letter to get the separate faces to extrude.

I am actually trying to make a case for some of our gear. Attached is the SU file for the lens I am working on. Ideally, the lower half would be 2" tall with an upp half that would cover the rest of the lens. I can not figure out how to convert this SU to a “solid”… and then move from there.

Thank you (from a New-B)

ET_DLE030 (1).skp (872.1 KB)

Well, there was a group of a few faces covering a hole on one side. The group needs to be exploded so it connects with the rest of the geometry. there are reversed faces–blue ones–that need to be corrected and then there’s a bunch of internal faces that need to be deleted.

Once you’ve taken care of all of that, you should have a solid component or group when you create it. And when you have a solid component or group, you can use the Solid Tool or better, Eneroth Solid Tools to create the recesses in the foam.

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I think the OP is talking about the CAD program Vectorworks. In that case (ha ha), I think sketchup is a better platform to attempt this in, as Dave has shown it can certainly be done.

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That it funny… too literal !

Yes. I use Vectorworks to CAD generation of meeting rooms… Not really familiar with the 3D world, but trying to learn. How do I find the internal facets that are trouble makers? Then… How do I do the foam recesion? Sorry to be a PITA.

Help is much appreciated.


I hid a face on the outside so I could see the internals. I selected those internal faces and deleted them.

Once I had the “cutter shape” as a solid, I drew a box to represent the foam and made it a solid component. Then I used Trim from Eneroth Solid Tools (from the Extension Warehouse) to cut the recess.

Getting closer… Thank you for the suggestions. I have a learning curve to tackle!


Alrighty… I have no idea what I am doing wrong…

Working_Foam_ET_DLE030_v2~.skp (914.5 KB)

Would it help to look over my shoulder so I can show you?

The main problem is that you managed to double “wrap” the geometry in each group.

Each of the bottom level groups is solid. Explode one or the other of the group levels so you only have each one with a single grouping level. and you’ll be in the home stretch.

OK… I deleted everything except for the Lens. Made sure the lens was happy. Turned it into a component… Then checked it with Solid Inspector… told me I was Shiny (I assume that this is good). Then I went and built a box. Did the same thing with that… Put the lens “On” the box. Attempted to “trim”… separated the Box from the lens… and got nothing new in either. Made a second attempt (with the already confirmed Box, lens… and got an error that the Box is no longer solid.

What god have I angered today?


Working_Foam_ET_DLE030_v3.skp (923.3 KB)

Try this model.
Working_Foam_ET_DLE030_v3.skp (65.5 KB)
The box group had a solid component nested inside of it so I got rid of the parent group and trimmed it with solid tools.


To help you understand what the solid tools are doing it’s important to know how the geometry works.
This is a simple version of doing it manually. Using a copy of your object you simply slice it and add the ‘box’. Note the reverse of the faces so the printing software understands what is inside and what is outside.

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Elegantly simple explanation Box - yet again!

Well… Got that part working (as expected, user error). Now I am trying to figure out how to export as G-Code… Or, STL for the CNC machine. X-Carve

I’m still unsure of what version of SketchUp you are using. If you are using SketchUp 2019 as indicated in your profile, it would be SketchUp Pro not Make. There is no Make version of 2019.

Assuming it is SketchUp Pro that you are using, you can export STL or other file types from File>Export>3D Model. Select the file type at the bottom.

It would be helpful if you fix up your profile with the right info about the SketchUp version and license type. Also put in what your graphics card actually is since that is often useful information when we’re trying to assist you.