An old colleague of mine went through the process of doing gridfinity. One of his main struggles was getting boxes that fit his power tools perfectly. He was looking for a way to easily get a shape of the tool into CAD. What’s the most straightforward and effective way to get a CAD representation of a solid these days? Of course there are expensive solutions but is there anything reasonably achievable in the DIY space?
Imho thats overoptimizing. To me the next larger square box is the best most flexible solution. I get the allure of perfect fit places for everything but to me its not worth the continuous effort. (I got several gridfinity drawers)
The common approach is to take a photo of an object from above together with a ruler or something of a known size for scale, then import that directly into the CAD software, scale according to the scaling object, and create a cutout along the object's outline. No need for calipers, 3d scans, or other complex measurement procedures. There are a lot of videos and guides on how to do that.
You could get a table mat with a measuring grid and take photographs of the object from different sides; three or more depending on how much asymmetric features the object has. Go as far away from the object as possible and use maximum zoom to get as close to isometric perspective as possible. If it’s not a very thick object, this method is millimeter accurate. With larger objects, the perspective will lead to slightly larger measurements at the object extremities: edges closest to the camera will be enlarged.
Then, in your CAD program, set up the photos as backgrounds for different perspective views.
Or, obviously, get a 3D scanner and live with the point cloud mesh approximations, it’s probably less of a hassle.
Or… just get a good set of calipers and a radius measuring tool.
Well if you want to get dirty and not deal with design, build a vacuum former. Shop vac, perf board, 2x4 or 1x2 frame and whatever rigid for a backer. Build the frames out of screen door frame pieces, and binder clips to close them. Polystyrene sheets are cheap af $.05 or less at any plastic supplier. Never been to a plastic supplier? I guarantee theres one relatively near by in whatever is your closest major city.
Use your oven to heat the plastic. Turn on the vac, pull out the plastic when it droops, slam down quick… perfect part. Lots of videos on youtube. Adam savage does a few on the process. Lots of nuance to the process to get really good pieces but for cheap, quick and good its hard to beat. Oh yeah the whole stormtrooper cosplay scene has done a lot of work on the setup, most definitely lots of improvements that I’m glossing over but like all rabbit holes its pretty deep.
I'm sure your colleague has done this already, but for anyone considering creating their own models, I would highly recommend checking whether somebody else already went through that process for you. A lot of things have been fitted into gridfinity. And even if not for gridfinity specifically, you can fairly easily adapt other existing models to a gridfinity based box.
There are 3d model search engines where I recommend just entering [item name] + gridfinity to find pre existing models. There is: yeggi.com and thangs.com (be aware that the latter recently changed to only display models from its own domain by default).
Photogrammetry is one. Generally results in messy geometry though and tolerances get finicky.
The CAD plugin in Blender is my favorite though. Need a caliper to get measurements and then I can build out my hooks/clamps/whatever. FreeCAD for when I just need sketches as I find the solid part workflow utterly confusing, whereas I'm very well versed in Blender.
> Photogrammetry is one. Generally results in messy geometry though and tolerances get finicky.
The trick is a hybrid approach, use photogrammetry to get a draft model into whatever environment you use (like Blender or whatever), then use that for creating the high-quality cutout manually, which will be very easy with a in-place 3D draft model right in the scene.
