Subtract Limits?

gothamb

Is there a limit to the complexity of the solids that subtract can handle?
I have two solids that i am trying to subtract. Essentially one is my work piece and the other is a "cutting Tool" to shape the other.
This should be a simple thing yet when i do the subtraction i get a huge mess of geometry comprising parts of both origional solids and the cutting tool is still present. furthermore is that the points of intersection that you would expect to be present after a function like this are not there either so i cannot even go in manually and remove the cutting solid.

Am i doing something wrong, missing something, is this a limit of this software or is this a bug that i have stumbled into? if anyone has any information it would be awesome.
this issue has been causing me headaches for a while and i don't know what to do.

I have included screen shots of the parts and the result of the subtraction function.

Thanks

(please note that both solids are water tight as far as i can tell, i used solid inspector and the solids have volumes present in the entity info window. furthermore the subtract function does not object to the lack of solids.)

main solid.jpg
This is the main work piece
cut solid.jpg
this is the "cutting tool"

notice that the result is not a solid any more
its hard to tell but this main solid is not cut at all and all geometry is still present.
this is what it looks like when you explode the resulting output.
it is not what i expected to happen at all.

SU file

Dave R

You're model is extremely tiny with a huge number of tiny faces. The limitation you are running up against is due to hitting SketchUp's tolerances. This comes up all the time here with users trying to model very small things. There's another current thread here in the Newbie forum in which TIG describes it better than I can so I won't repeat it. Try scaling your model up by a factor of 1000 and see what you get.

gothamb

Thanks. i will check that out.

TIG

This is a 'clipping issue' - it's well documented.
Change between Perspective/Parallel Cameras to fix it.
It's usually caused by having some loose geometry miles from the model's origin ?
Or a component with its origin miles from its geometry.
Especially noticeable in CAD imports where you have perhaps kept the origin ?
Test to see what it is...
Model Info > Statistics > Purge unused & Fix problems.
Switch all Layers ON and View > Hidden Geometry ON
If you Select All [Edit] and use Entity info it gives a count.
Zoom out so you can see everything you expect to be in that selection...
Now use Select with a fence holding Ctrl+Shift to remove those items from the selection.
Are there still items in the Entity Info list ?
Try to establish what they are.
You can probably hit Delete and remove them and the clipping should stop.
If you think it's a component origin issue...
Model Info > Components > tick Show Component Axes...
If any component-instances have issues use the context-menu to Change Axes to something more logical...