Can't trim objects

So I have 110 closed solids that I want to cut the top off, or see the inside of at least (also tried boolean but didn’t work neither in rhino nor maya), but understandably it’s having trouble. I have a pretty high end pc so it shouldn’t be that. I am using a line to trim off all of the parts of the object above that line.

Anyone have any idea what to do or an alternative to get the desired result?

post the file?

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Extrude the line to a plane that intersects all the objects, then explode it to convert it into a surface and then use it to trim? Or instead of using a line in the first place, just create a rectangle directly from the surface menu?

If you just want to see inside a Clipping Plane might do the trick.

The trim may fail if the solids aren’t actually watertight - I’d check for naked edges. Check for bad objects too, any bad geometry could cause issues. If you are using a line to trim, presumably from a orthogonal view, make sure Apparent Intersections is turned on. IIRC correctly it won’t work if that is off.

Trim does not be care if an object is watertight or not.

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Tried that, no go

Are those ‘solid’ objects meshes by any chance?

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Clipping plane trims the object but leaves the top surface on. Also I want to be able to finalize the clipping action so I can render it in different software.

The objects were created by extruding 2d surfaces, so there’s no naked edges. Also, if I select all, it says closed polysurfaces

nope, all made in rhino by extruding rhino-made surfaces

Preferably not. It’s an artwork I’m making and I’m a little sheltered about posting that stuff if not necessary. Sorry

OK, I guess you’ll have to post an example, maybe just a few of your solid objects and the line you want to use for cutting… without an example file, impossible to guess what’s going wrong unfortunately.

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Create a generic object that has the same behavior and post it. Or Export one or two objects, modifiy them if desired and post…

trim difficulty.3dm (3.4 MB)

I modified the file. Tried again, this time after a few minutes and cancelling the process, some object did get trimmed, but it’s too long a process to be doable in the long run. Also seems strange that after 3 minutes so little was done considering how simple the process is.

Thanks for all your support :slight_smile:

Is this what you’re after? If so, just call ExtractSrf and window select the top surfaces in the front view, then delete them. trim difficulty open.3dm (3.1 MB)

Sweet, we’re almost there. The only problem I have with this method is that a pre-selection of the bottom surfaces is annulled as I call the function. And when the function is activated, I can’t select the surfaces anymore. I can only select everything or nothing for some reason (as in every surface from each polysurface, not every object).

In that case I can extract every surface and delete the bottom ones, but it’d rather keep the surfaces connected. It did make me realize that exploding every object and deleting the bottom surface was an option all along, but I found that you managed so let me hear your secret please :smiley:


For me, I was able to call the command, ExtractSrf, then select the surfaces to be removed with a simple windo select in the front viewport. They remained selected after being extracted, so I could just delete.

You’re absolutely right, David. Trim doesn’t care if the an object is watertight. I was recalling past experiences trimming multiple “solids”, I’ve found that you don’t always get the expected results if all of the objects aren’t actually watertight. But of course the trim should still work on open objects.

I downloaded your file and trim worked as expected without problem. Mine is far from a high end PC (it is decidedly elderly) but the process of trimming only took a few seconds.

I found 92 closed polysurfaces, no naked edge etc. There were two duplicates but they didn’t seems to cause a problem. I used a line to trim and it worked perfectly - perhaps I’m misunderstanding what you need.

I tried it again upon reboot, and now I was able to select just the bottom surfaces. So your method finally allowed me to finish my artwork. Thank you :smiley:

No, you’re totally understanding me correctly. But somehow this method just doesn’t work in my case. And I do actually have a high-end pc, which exactly shouldn’t matter because of how simple a process it is.

Luckily extractsrf does work for me :slight_smile: