Need some help editing this STL file

In the image is the file i need to edit. I have been printing hands for children who do not have hands.

The file i print has TONS of retractions on the first few layers. I want to make the grid pattern a different shape than rectangles. I was thinking circles since that will be less retractions for the printer. I need some help figuring out the fastest way to fill all the rectangles, and then be able to make holes. The reason for the grid shape, is to thermo form it by placing it in boiling water and forming it around the wrist as it cools.

i know i could use the pencil tool and fill each one in, but that will take forever. trying to find a more efficient way:)

Palm_right.stl (6.6 MB)

Working with imported .STL files can be a big triangulated mess. A few things could speed this process up here. First, configure your import settings, import the .stl into SketchUp with the units set to meters to avoid the tiny face issue (stl is a unitless format anyway) and check the merge coplanar faces to save yourself some headache.

The resulting import will still be a big glob of raw geometry, but you can use a section plane to avoid selecting unwanted geometry and get the bulk of the boxes deleted with some basic selection. Still some detail cleanup on the non coplanar edges but not too bad.



ok, great. i do not work with stl files very much. The next part is to create circular holes in the area where the rectangles were. Not as many but enough to help this part thermo form correctly.

I doubt the part is a solid so i will probably have to use intersect faces to make all the holes.

i will give this a go and see how it does. My pc has a 12 core cpu in it so hopefully thats enough to not cause crashing haha


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Or draw circles and push-pull them through…

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If it’s not a solid it won’t print correctly. You should fix that before you worry about adding the holes.

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The part is not solid, although it’s desirable but not strictly required to print. Some slicers can deal with a few small mesh holes OK. I don’t know the one you are using, perhaps it time to look into another slicer? With the mesh fixing options on, Cura was happy to slice this.

The two faces that the rectangle holes were removed from are coplanar, so I was able to array some circles on one face and push pull them through to the other.

SketchUp, like all CAD operations, is single core only, so can’t take advantage of your 12 cores. Clockspeed and RAM are what matter.

ok, i followed youe gif exactly, and everytime i select the rectangles from the top view and erase them, it takes the entire bottom with it. Whats the trick to just selecting the top lines and not everything else?



hidden geometry was the issue

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Yes there is some non coplaner clean up on t he boxes around the edges. I could do most of the center boxes in one go, then show hidden geometry and work your way around the detailed ones.

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i have 2 ideas. 1. remove all the small boxes and then add circles, or combine some of the small boxes into larger ones, say, every 4 boxes to make a large box. Its just ment to help thermoform the plastic in boiling water haha

A really wonderful and worthwhile endeavor I think, designing for all the right reasons. Either circle holes or joining the boxes should work. Is there an inner sleeve material that goes between the prosthetic and the skin? If not would the circles yield less sharp edges for “hotspots” or chafing? I know next to nothing about designing prosthetics but I’m curious.

Here is a baseline .skp 20 version with holes gone and a cleaned up lower surface.

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Forgive me if I am over stepping, I got intrigued with the project. I made a version with an octagonal grid of holes that are chamfered by .25mm to soften the edges. I have no idea if this is desirable or not, but the general practice is repeatable for any shape or edge profile. I created an array of components outside of the hand context, then pasted them into the same context and exploded them to cut all the holes at once. There are a couple of tricks to this process that make it much easier if you are interested.


i am very interested in the process. I tried to make mine a solid last night and had no luck haha.

the reason to get rid of the rectangles is to reduce the number of retractions the printer has to do. SO i either have to make them larger or use larger cirlces.

also, here is the website for the group. I just printed 50 of these hands at school

Team UnLimbited

thats the problem of using f360 or solidworks for school the last couple of weeks… i forgot about push pul haha

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did you use an extension to do this or just basic tools?

Basic tools, Not time now but I’ll make a quick tutorial when I can

Make a component with closed ends that match the top and bottom planes. Make this outside the context fo the hand but inferencing the top and bottom pate.

Give the end faces only a shared material. Reverse the side walls.

Array the component in a desired grid

Copy / paste in place the array from outside to inside the hand context

Still selected… Explode all components of the array

Select one end face with material, right click select by material


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I found a moment…



yeah thats the way i did it as well for larger squares or circles. I was just noticing on your hexagonal shaped version, some are cut in half and i was wondering if you had to manually trim those or if there was an extension like solidworks has where it detects the boundaries and will cut the shapes automatically:)

Manual trim.

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