What size of test grid do you have? Are they in a specific pattern? What is your method for hooking the movement of the effector and changing the z value? How often do you need to run the loop and how much computation time do you have to do it?626Pilot wrote:Math time...
I have a question about finding a point on a 3D mesh made out of triangles, the vertices of which are the test points on the print surface. If I probe the surface and get a bunch of depths, I have a "mesh" approximating that surface. I need to use that mesh to correct for Z.
I assume that in order to get the right depth for a given (x, y), I have to find the nearest triangle of that mesh and then somehow turn the surface normal into a depth.
How do I do that really quick (since it will have to be done 100s of times a second) and with the smallest memory footprint possible? I don't know that much about computational geometry. Help me find the right answer, and I will help you print!
Wild assumptions below:
Assuming you have something like a 9x9 test grid (for example), I think the best way would be to have a running loop of what triangle you are currently in and track when you cross over to a different triangle. At the start of the print, it is easy enough to use any method initially to determine your first triangle location and then once you have done so you can take the input vector of the movement for each g-code and determine which triangles you are going to cross over the next x seconds. Then you simply need to have a loop that tracks when your <x,y> has passed into a different triangle. Since you know what triangle you are in at any given time, you can simply have a calculation loop which runs every .05mm or whatever that calculates using simple geometry the z-correction and passes that on.
Also no nasty head crashes or attempts to wander off the print bed.
Somehow I had neither delta_segments_per_second nor mm_per_line_segment set in my config so that's why long moves were curved!
