I don’t have good access to a 3D printer and I like the idea of the maslow cutting it’s own accessories so I am trying to make a tool that will slice a 3D model into cutable layers. I know it will be rough but I think it will work ok for what I need.
It is working ok but it keeps crashing or hanging in different places. I think it is just too much computation at once. If I reload or recalculate it still hangs. Is there a thing that I am missing? Each piece and each slice seems to compute ok individually or in small groups. I guess I would like a way to just reload or recompute a small part of the model at a time. Targeted recomputing seems like it would help.
At this point I think I have checked all of the slices individually and all of them work except the two that are missing in this picture. Slices 8 and 9 won’t compute?
This seems like a bug (or limitation) somewhere inside of the OpenCASCADE cad kernel which does the underlying math. It has some limitations like no parts can be zero thickness, and also some bugs.
That looks like it’s where the bit-area cutout meets the sloping surface. If the circle of the cutout precisely meets the line representing the edge of the sloping surface, you may get some weird math with flat triangles, polygons that intersect at only one point, and other stuff that geometric software really doesn’t like. (I do a lot of work in Openscad, which can get similar issues, and sometimes the best solution is just to move things a bit.)
Ok, so bugs and fun results. It worked to place a block and fuse with the original shape in the bad geometry area. I could proably pin it down more but I am happy at the moment.
My computer is probably too weak to compute a whole project well. when I tried to recompute it stalled and all turned red. If I went into each molecule and sub molecule (all are internal molecules in this project) and poked each one it would compute and then I could move up a level. Eventually it all computed.
In the assembly I had a couple of blank layers. The cut layout really didn’t like them. It didn’t like having empty things handed to it. I went and disconnected each one and then ran cut layout again and it tried.
Hi wouldchuck! Thanks for the detailed notes. Great to know about blank entities messing up the cutlayout, that’s something we’ll definitely want to fix.
First question about this project in particular, how thick are the slices that you’re extracting?
I can add a bit more context (tho not an immediate solution) to the cutlayout behavior here which may help clarify what’s going on. Cut layout operates in two steps
for each input, choose which face should be down, ie aligned with the underside of you material
using the perimeter of the selected face, pack pieces into sheets as concisely as possible.
What it looks like in this case is that step 1 is going wrong. The criteria for picking the underside face is best-effort and has the following criteria in order: 1) the face must be a plane, 2) picking this face must not cause the part to protrude below the sheet material. 3) prefer to minimize height*, 4) prefer against interior lines within this face (eg: since these might indication voids that’d be unreachable on the underside of the stock material)
I have a sneaking suspicion that this is related to the logic around minimizing height. Basically cutlayout tries to guess your material thickness but we abandon this criteria if material thickness is > 1 inch or 25.4 mm. So if your slices in this project are thicker then that, the current cut layout system will effectively disregard height when picking layout, and since a lot of these forms have interior loops on their big sides it’ll end up choosing some tiny end that happens to be flat.
Does that seem consistent with the behavior you’re seeing?
In the short term I’ll work on fixing cutlayout’s behavior when input forms have a thickness above 1”. Longer term Bar and I have been discussing splitting cutlayout into two molecules, one of which does the face selection described above and the other of which does the packing. This would allow you to skip the first molecule and feed in pre-oriented parts. I think this long term approach offers a more robust solution to this kind of misbehavior of the cutlayout molecule.
for each input, choose which face should be down, ie aligned with the underside of you material
Why do you need to figure something out about this instead of just having the
bottom down and let the user flip it in the fairly rare cases where the bottom
isn’t flat?
Thank you, : )
In this case I set it to 3.175 mm (1/8 in) in the slices. The pieces are overall kind of 5 by 6 inches. I could try other thicknesses just to see if the behavior changes? The pieces do look like they are standing on a tiny end rather than reacting to the planar cut side.
I would appreciate more accessible control over the end layout I need to make it fit my wood, the grain direction, flip one side up or down. I like automatic things but in the end what I need are the pieces laid flat and then ready for me to move around to fit in the space that i need. Computers aren’t good at packing. Humans are. I am bad at rotating things in three dimensions to lay them flat, It feels like computers can maybe do that well. I will have requirements and needs about surface and milling and direction that the computer won’t know so I will always have layout adjustments. I need to be able to flip and slide and rotate easily. I would also like some way to separate actions like drilling, surface cuts, and cut throughs.
I don’t expect it to work yet and I know you folks are doing a lot of work. I am having fun playing with it. Thank you again,
It all stopped calculating at basic equations in the molecules. I don’t know what is happening. I have reloaded, reacalculated and then when I went in and deleted the basic intersection nodes one by one and then rebuilt them finally those ones came back. I have problems with the cascading calculations not working. Is it my computer? or is it the system?
