V4 – New Slice Command
I’ve always disliked the slice command in MeshCAM until now; it’s ugly, unclear, and inefficient. The Customer Experience Program showed moderate usage even in this sorry state so I figured it might get real use if I made it better. The new slice command is not just a trick of defining the stock to only machine one slab (like the old command), it will instead save a batch of STL files- each one representing one slab of the model that can be loaded and machined separately. An example of one of the STL slabs is shown below.
There is only one problem- parts with undercuts look funky. I am taking some geometric shortcuts to generate the slices that make the system as robust as possible. Undercuts end up with big planes above them that, while technically correct for a 3-axis mill, are ugly. I’ll be curious to get feedback on that part after release. I’d post a photo of that but I’m in the middle of a rebuild and the blog post gives me something to do while waiting.
“Undercuts end up with big planes above them that, while technically correct for a 3-axis mill, are ugly.”
Robert, could you color those planes red? From your description they do function as check surfaces, and that would be consistent UI-wise.
Randy
They do serve the same function as a check surface but since they are saved in an STL file I don’t have an easy way to encode this. STL files are just buckets of triangles.
I think I’ll have to play with other programs that do this and see how they handle it. I know that I can fix it a couple of ways but they all have different use cases. And they all take a long time to code.
-Robert
OK, gotcha, Robert. Can you keep track of the capping surfaces you’re generating and save them as a separate STL to be loaded as a check surface? That sparks an idea–saveable STL sets–a main STL and associated check surfaces that can be called up as a set. That would save some user work on repetitively called up models, and a main STL might have several check surfaces that allow detailed machining of different areas, so multi sets based on one main STL…
Randy
Randy, wouldn’t that be the same thing as “Don’t machine top of stock”? Just seems redundant.
No, Gerry, I have models where the bulk is machined with, say, a .250″ ball-end and then specific areas (recessed logos, etc.) that will be machined with different cutters (maybe .020″ ball-end, .020″ flat-end, etc.) that I’ll “mask” individually. I haven’t had a model that used more than 3 finishing cutters so far, but I’m thinking that it might be a handy facility. Until check surfaces came out (and I understood how to implement them
) I would cut out areas of the solid model and export separate STL’s for the remachined areas.
Randy
Randy-
The flat surfaces that end up acting like check surfaces would not obscure any part of the model that would be machined if the whole geometry was processed as a single part rather than a slice. I thought about making the slice command, “The best slice command ever” to handle every case but I think if you move beyond the simple case of a 3-axis job being too tall for your mill, you’d be better off handling the slicing in your CAD program.
For instance, slicing an STL and then running a 2-side machining job on both is something you should do in CAD so you can optimize the slicing planes.
-Robert
Oh yeah, I know that, Robert. I think I’ve just drifted your topic a little…
I still think that “STL sets” would be a neat feature… You suggested modeling supports as a separate STL when their location was uber-critical, and I have taken to doing just that on my latest models, which I do also section in the CAD program (though not orthogonally like slices, but to ensure the maximum outer and inner geometry is machinable with 3-axis). so loading the STL and supports in a single stroke (and yes, maybe a check surface or two) would be nice…
Randy
(sorry for the topic drift)
There are a few hacks that I could use to encode that in an STL file but they’re meaningless since no CAD program would do it.
I’m sure that you saw the note that I added “Append as check surface” to the File menu. Hopefully this will promote it to a first-class feature and not something hidden in the background. I use check surfaces all the time so I hope this will grow to be a popular thing.
-Robert
“I’m sure that you saw the note that I added “Append as check surface” to the File menu.”
Yes, and I appreciate that, Robert. Oh hey, I just discovered (now that I thought to check, doh) that “save job” includes any appended check surfaces, and keeps them red…so in the words of Emily Litella, “never mind”.
I can save job variations to my heart’s content.
Randy
I should have mentioned that- I forgot about it too. I use that everything I create a new job with check surfaces so that I don’t ever have to worry about reloading the combo wrong if I need to remachine anything.
-Robert