I need to subtract the two vertical extrusions from the base polysurface to make channels in the base. The boolean difference function will not work. All polysurfaces are closed and I’m not able to find the cause of the fail.
thanks,
rex
mcneelsub.3dm (2.0 MB)
What exactly do the vertical extrusions look like? I don’t think they’re included in the file.
Whatever you’re planning this will likely be a problem:
There might be a solution that involves a different approach but I won’t know for sure unless I know your intended end result.
Sorry, but not based on what I am seeing:
Intersection curve ends at a naked edge.
open polysurface
Selecting everything visible upon opening:
Found 367 edges total; 13 naked edges, no non-manifold edges.
They all seem to be along the middle object at the top of the base where the exclamation marks are.
Here’s a new file. I’ve hidden all the extraneous stuff so that only one poly surface shows. This is a close solid polysurface, but it still has the 4 black spots. Shownakededges doesn’t reveal anything. I’m not sure what those dots are trying to tell me, but I do think they’re the crux of my problem.
mcneelsuba.3dm (2.0 MB)
The black dots are in a group. click on one to select the group, then look at the Properties panel for the group. It tells you:
The four black dots will have been created by a previous operation, as a warning message (you’ve cleared out the geometry they related to). The intention is that once you’ve read the warning (and taken any pertinent actions) you should delete the group.
Going back to the first file, your boolean difference is failing because of an issue unrelated to the black dots. Your subtraction objects have sides that coincide with the shallower slots you previously made in the base. Booleans often don’t like coincident faces.
Isolate the base object and explode it. Delete all the faces of those earlier slots, then untrim the holes in the top face. Join everything together into a closed polysurface - taking you back to where you were before your previous subtraction. Unisolate and you will find the vertical pieces will now happily subtract from the base.
HTH
Jeremy
I’ve now reduced the number of objects and only have the two I want involved in the boolean difference. Both objects are closed solid poly surfaces. I’m trying to subtract the tall object from the base object to make a channel in the base object. Continues to fail.
mcneelsubb.3dm (2.0 MB)
That did it. Makes sense and it works. You’ve improved my Rhino skills another step.
Thanks much,
rex
