Subtract is only working once

[lisetteterry]

Hi I am using AutoCAD 2010 to create a 3D model.

I am trying to subtract multiple objects (conduits) from one single object (a thick concrete pad). I created the thick concrete pad by defining two profile shapes and lofting it to create a solid. That works fine.

Now for subtracting the conduits (which are also solids). I say subtract, select the concrete pad hit enter then select one conduits. Voila, it looks great and is subtracted.

Here is the problem: Now when I try and repeat this exact same thing it will not subtract the other conduits from the concrete pad. I have tried each conduit individually and they all work by themselves (granted it the first solid I am trying to subtract from the concrete pad).

I have tried selecting all the conduits at the same time in the subtract command and none of the conduits subtract from the concrete pad.

Does anyone have any idea why this might be happening? It is really frustrating because I know I am working with solid objects here and subtract should be able to be used multiple times on the same object.

Thanks for your help!
Lisette

[douglass]

I've had similar issues with Mass Elements in ACA2010, once my main mass object reached a certain complexity it would not accept additional boolean operations.

I don't know why this happens, and I realize Masses and Solids are different animals all together, but I have one suggestion for a workaround:

Union all of the conduit solids first (or make a copy of them and union them just for subtracting purposes), then subtract them as a single solid from the concrete pad.

[lisetteterry]

Great idea; I will try to union all the conduits together. *crosses fingers* that this will work. Thanks! I will post the result of what happens.

[lisetteterry]

Yeah unfortunately union didn't work. It is not accepting one piece of my conduits as a valid solid. I am going to update everything to a "valid" solid (which means re-drawing every single profile and lofting the solid shapes) and recheck.

Thank you though for your help!

Lisette

[jaberwok]

Just recreate the one bad piece - if possible, copy from a good piece.