Subtracting Solids

[scott moore]

What is the deal with subtracting solid 3d objects? It is a great idea, but it seems that the application remebers what has been subtracted. Every now and then I get a "ghost" rectangle or polygon that shows up when changing views. I know that these are the objects I drew to subtract from an existing piece. Occasionally, the odd shapes will actually replace the finished object At other times, an unwanted shape appears and it cannot be selected or deleted. What gives?

[Dane]

Hi Scott, I have run into the same anomolie. I'm not sure why it happens but to eliminate the problem I do trouble subtractions in a separate drawing (you could also use a separate layer) and just copy my final part and paste it in my working drawing.

Dane

[broesler]

This response may not address the specific problem you are having, but I have found in creating 3D architectural models that once a boolean operation (add, subtract solids, etc.) has been perfomed, VW remembers the XYZ coordinates where the operation was performed and if you then duplicate the resultant object and move it to a new location, the new object will decompose into the original components at the original XYZ coordinates of the original operation if you for some reason "ungroup" it. I work around this potential problem by always performing boolean operations at the XYZ coordinates where the final object will reside.This does not create a problem with my work flow, and ultimately seems to provide a simple way of keeping up with everything. Even now though, I sometimes find I have inadvertenly ungrouped a object created by boolean and have to go through the process of figuring out where the pieces went, bring them all to the proper coordinates and then perform the operation again. Sounds like a pain, but it's really not.