Horizontal size compensation?

[amcutem]

I hope this is not a stupid question, but let's say I printed a 30mm cylinder with a 10 mm hole, and then I added a 1mm value.

I think I'm right if I say that the outer cylinder will then be 32mm, but then I don't know what will happen to the 10MM hole?

I guess it can only become 12mm?

[JoeJ]

No, it goes inward. If you put a positive value in for the size compensation, then the part grows outward everywhere. So the hole would become 8mm.

If you put in -1mm for the size compensation, then the outer cylinder would become 28mm and the hold would become 12mm

[C-line]

This feature can be a bit confusing at first.

The way I like to think of it is as if your part was a sponge. If you use a positive value for Horizontal Size Compensation it's like wetting the sponge: it grows in all directions, with the outer perimeters moving outward and the inner perimeters moving inward. If you use a negative value it's like drying out the sponge: it shrinks in all directions, with the outer perimeters moving inward and the inner perimeters moving outward.

Hope this helps!

[dsegel]

Also, because the dimensions are changing everywhere (in X and Y) you usually want to use very small values, like 0.1mm or even less. If you need to overcome a larger fit issue than that you may be better off just scaling the entire model.

[KC_703]

Yes... positive inflates and negative shrinks. Sponge is good analogy.

Best way to understand this may be to see it for yourself. Load up a captive planetary gear, slice, view the preview... then re-slice and preview using different horizontal size compensation.