Adjusting model for tolerances

Not sure if I’m using the correct verbiage, but this is what I am trying to do. I use Sketchup to design a mold to print on my 3D printer. Everything works great. It’s a mold that will hold pieces of wood that are glued together first, then put in the mold to hold them together while it dries. The wood is 3/8" square. It’s really tight fitting. I have many square faces on the mold and I’m having trouble moving all the faces by a small amount (like 1mm) to give the wood a little room and not be so tight. Is there an easy way to tell sketchup to shrink all faces by a tolerance or something that wouldn’t require I go and move every face individually?

Can you post the file so we can take a look? The first method that pops to mind would be using the scale tool. You could select your mold and scale it by 1.0001, or more or less.

Piece_01.stl (4.0 KB)

I uploaded a sample. The problem is, I use pre-cut pieces of wood that are 3/8" and they are real tight. I have a lot of these molds and I was hoping there was an easier way to shrink the solid piece. I use the term tolerance, but I’m not sure that is correct. Does that make sense?

How about uploading your .skp file.

The issue you’ll run into is that you’ll need to figure out how much shrinkage you’ll get in the print. Then you’ll need to make allowances in your modeling.

Make sure you turn off Length snapping for Units.

What version of SketchUp are you using? Please complete your profile.

Had a quick look. If most of them are that simple, a few repeated uses of PushPull on selected faces in SU would give you the clearance you need. If 1/64" is too much, then switch to decimal inches and experiment from there.

I’ve found working in millimetres on an FDM printer, that it prints outside perimeters about 0.5 mm oversize, and inside openings about 0.5 mm undersize. The print head tracks the centreline of edges, and my print head is 0.5mm, so adds 0.25mm on either side of the line.

On top of that, you need a little bit of clearance so the 3/8" squares are a nice push fit.

So experiment.

Thanks John, that’s exactly the approach I was taking. I just thought I would throw out the question in case there was a simple solution.

I don’t think Scaling is the answer. And there really isn’t any other simple way I can think of in SU.

In principle, someone could write a Ruby program to iterate through selected faces and offset them by a given amount, but selecting them first is barely if at all quicker than a double click pushpull to repeat an already established distance.

And I doubt if a Ruby program would be clever enough to work out which faces to move.