Intersecting Groups
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Hi all. I am having a problem insecting groups. When I intersect non groups, everything is fine. I get a nice solid cutout object. But when I have two groups and try to intersect them, I get a hole instead of a cutout. I am selecting the group before I do the intersect and remove the lines, so I don't know why it is coming out this way.
See Example
Can anyone provide some insight?
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Hi Klack,
That's the way it works. When intersecting geometry, SU will create lines where the two pieces (edges and faces) cross each other. These lines are always in the same editing context you are in. So if you are outside a group, the lines will be created outside also thus not become part of the group's geometry and they won't actually intersect. It's like drawing lines on top of a (closed) group: they will never be part of it.
You need to have both entities (two sets of geometry) in the same context. Either outside of a group (like exploded) or both inside the same group.
Of course, this is "plain" or "native" SU. With plugins like BoolTools, two groups can be intersected in various ways (this one is a commercial plugin however).
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the important thing to remember with intersections is that the new geometry is always created in the current context.
this means that if you go in to a group and do the intersection, the new geometry is created in the group and will not effect anything outside the group.
To work around this, you can ctrl-c any geometry you want to intersect inside the group, then go in to the group edit->paste in pace and then do the intersection.
edit: beaten to the draw!
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Not sure if I am getting this. In the picture to the right I did select the group before I did the intersect, and the geometry was drawn on its face. Only it did not drawn the 'bottom curve' to complete the 'inside face'.
The only reason I want to keep them both grouped is because I want to keep both pieces and not have them stick to each other. Is there a different way? I suppose I could pace the two groups where I want them, explode them, intersect them, separate, and regroup, but I'm trying to avoid that.
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The "same editing context" means that you cannot combine two groups like that. What you could do is to edit a group,select all geometry inside, copy it, close the group and "Paste in place" (Edit menu) outside the group. Do the same with the geometry in the other group and when they are both outside, do the intersection.
Think of groups like separate SU models that cannot interfere with each other.
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Thank you, with 'Paste in place' I have archived the desired result. Two objects that have intersected each other, and are now grouped separately. I'm guess the intersect tool was designed with the idea that one of the objects will always be erased, and I was using it in the wrong way.
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Indeed, that would be the "average" use; to end up with one object and delete "unwanted geometry". I see that you practically needed two different objects and this means two different operations - but at least can be done this way.
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