Touch Probe

[Jonathan]

My freebie probing software project for Mach might be of interest. http://www.razordance.co.uk/probe25D.htm

I read that a few weeks ago but couldn't find the link ... thanks. It looks like a good idea, the only problem I can see is if the height of the edge of the part you are probing varies significantly it's not accurate.

[stirling]

the only problem I can see is if the height of the edge of the part you are probing varies significantly it's not accurate.

Not accurate my be a poor choice of words - it's as accurate as your system in that it'll give you the edge at the height you probe. Sure, some shapes may not lend themselves to this process as well as others - welcome to the art of probing and every 3D analysis system there is, whether it be laser, contact or even MRI. None can cope with every shape and material. Like everything else, you mix and match and choose the right tool for the job.

[Jonathan]

Not accurate my be a poor choice of words

Probably, I was never very good in English lessons...

I guess all you have to do is change the probe tip to a simple cylinder that's at least as long as the height of the piece. The only issue is as the cylinder pivots about the top it will give a slightly different reading depending on the height. Easily compensated for by just drawing a contour round the path generated (or using a much longer cylinder) and accepting it may probe a little of the bed.

Alternatively you could probe the edge at different heights then generate the path from the limits of those, but that's going to take a while.

[stirling]

I think you're running a little ahead of yourself and perhaps missing the point of what this is primarily meant to do. The idea is to create a profile which is then used to constrain a bed o nails type probe. How you go about creating the profile is up to you - you can skip the edge probing and draw it in CAD if you like. You just then feed that into the 3D routine. The edge probing is there to help with that if it's appropriate. You might want to try it before you think up all the reasons it "won't work" for some given situation. This routine has been in use for several years by pros all over the world from luthiers, gun stock makers, reproduction moulding manufacturers to name a tiny few.