surface trimming

[TERRY]

Could use some help with a problem that two of us are having with trimming surfaces to curves. Not sure if it's a bug or if its something were doing wrong. I'm fairly new at this but our other guy is having the same problems and he has been using mastercam for quite some time. We are using Mill8. In many cases I am not able to trim surfaces to curves (keep getting the "unable to trim surface, selected chain does not form a closed boundry" error message) Now i know without a doubt that the chain i am selecting is closed and flat (have checked and triple checked, even squashed to make sure it was a flat 2d contour) Have also tryed every concievable cplane and normal and view, yet sometimes it allows me to trim surfs with single oen chains in other situations. If anyone is familiar with this problem or this operation your help would be greatly appreciated. Thanks, Terry

[camguy]

If the surface is already trimmed, untrim it. if the curves are close to the edge of the surface, extend the untrimmed surface past the trim boundaries, make c plane and g view the same, then trim. i have noticed that sometimes if i am in isometric view, and i want to trim a surface normal to front or side c-plane, it will not work. hope this helps.

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[bstall]

Sometimes when I can't get a surface to trim with curves, I will extrude a surface using the curves straight up and use the trim to surface function instead of curves

[TERRY]

Thanks for the replies. Both sound like they will work. Have looked at the untrim surface function but was not sure how to set the dispose option or not sure if it really mattered either way. Another thing about the surface I was trying to trim is it was a flat complete closed circle about .05 wide. I thought that because it was a complete closed circle maybee i had to break or split it first but was not able to find a way to do either of those. Thanks again for the help Terry.