Slicing
If you’ve been following the support group you’ve see that there’s been a lot of discussion about adding the slicing mode that was in version 1.18. I removed it in V2 with the intention of adding it back in but never got around to it. Yesterday I began writing code for the new slicing mode and came across the old disabled command from 1.18. I reenabled it and, to my surprise, it worked well. The old dialog did not support mm and inch input so I had to fix that. The images were not up to my current standards so I redid those as well. If my testing goes well it could be released within a week or so.
Build 6701
Jay H. pointed out a bug in the latest releases where the geometry supports are ignored when a toolpath is calculated. I fixed that and posted a new release at http://www.grzsoftware.com/files/MeshCAM2-6701.exe . Try it out and let me know how it works.
Build 6699
Jeff D. was the first to point out a significant bug in the latest releases. It turns out that the finish path could gouge if the roughing tool was much bigger than the finishing tool. This was due to a bug in one of my optimizations and has been fixed in 6699 at http://www.grzsoftware.com/files/MeshCAM2-6699.exe . Build 6699 has a few other little fixes and tweaks in addition to the big bug above. I also added Lua scripting access to modify some of the internal machining parameters for the real tweakers out there. I’ll try to post a Lua script in the next few days that will describe the parameters and show how to modify them.
Build 6689
OK- the testing went better than I thought so I’m posting a new release here for everyone here to try out. There’s still some improvements to be made for the pencil and waterline paths but in all of the testing I’ve done over the past few weeks of development it seems much better than any of the previous releases. Let me know how it works.
http://www.grzsoftware.com/files/MeshCAM2-6689.exe
New Finishing Option
In the past people have requested a way to have the finishing toolpath ignore the top of the stock if it’s just going to try and machine it flat. This would be a great option if you’re trying to machine a mold or something similar where your stock is already machined on the top face. When I redid the code for the parallel finish I made sure to add support for this feature. I planned on waiting to add this option to the dialog since it would require modifying the code for the dialog- never a fun thing to do. I ended up having to do this anyway for the new toolpaths options so I went ahead and enabled the new feature, “Don’t machine Top of Stock.” Below is a shot of the new option to look for and the results.
I’ve probably got another day or so of testing and then, if all goes well, I’ll post another test release here with all finishing converted to the ZMap-free versions. I’ll be looking for lots of feedback so please keep an eye out for it.
Pencil Progress
The pencil algorithm is starting to work well now. Simple paths are no problem as shown by the star shot below. To get paths with some potential ambiguity, like the standard “Cheese Whiz” model, to work I’m going to need some more code and testing.
The screen below shows how the internals of the new system work for pencil machining. The system builds a series of x and y passes to find all of the features of the model. These passes, shown in white, are sometimes called CL nets , short for cutter location net. The spacing of the lines is calculated from the tolerance value and the cutter information entered in the toolpath dialog. The spacing of the lines can be relatively wide compared to the old ZMap spacing because each of the line is subdivided along its length to ensure that nothing is gouged.
Pencil points can be found on the cl net by looking at the angles of the lines that make it up. In the photo below red boxes represent the pencil points with green lines pointing away from the model at each point. The shot on the right shows the points only for more clarity. The weird paths shown above are due to problems in connecting all of the pencil points since it’s difficult to calculate the correct way to link a bunch of points with no real information about how the real surface is laid out.
Current Status
The bulk of my time has been spent on trying to get a good toolpath coverage when both waterline and parallel finishing are being used. This turned out to be difficult to calculate quickly and accurately- the two characteristics always oppose one another. After trying about six different approaches I think I’ve got a good approach. The photo below shows the current status. You’ll see that there is some overlap between the two but there is very little “spiking” near the threshold like the previous versions.
In the course of doing this I’ve made a number of decisions that will probably cause controversy. The photo below shows one such case..
Older versions of MeshCAM would have cleared each top separately and then gone to the flat bottom. The new version sees each surface as a connected flat surface and machines them all together. This is the biggest change in the toolpath algorithms- the way that surface angles are classified. I can make it more like before but there will be the tradeoff of accuracy and speed. Comments are welcome but the photos above show what will be in the next release that I’ll post here (not on the main download page).
I’ve moved on to the pencil machining for now. This should go quickly- maybe a week- and will totally eliminate the ZMap from all finishing toolpaths. It’s been a long path but it’s finally coming to a point where it can be shared in a more public release.