Forum: Carrara


Subject: Nasty artifacts on boolean objects???

Nate opened this issue on Aug 02, 2002 ยท 5 posts


Nate posted Fri, 02 August 2002 at 10:51 PM

The object with the weird wavy pattern was created using booleans in Carrara 2. The surface was a fairly basic darkish chrome, but when rendered it results in this ugly wavy thing. It is not moire, and it seems only to happen on some objects made using boolean operations. Any ideas on how to get rid of this mess?

Thanks!


On-line portfolio / Making figurines in China / Gallery  / Video Demos


freedomsun posted Fri, 02 August 2002 at 11:45 PM

Attached Link: http://www.freedomsun.com

also, on topic, sometimes a Boolean subtraction will not retain smoothness. For example a wall subtracted from a curved shape will become polygonal rather then smoothly curved.

AzChip posted Wed, 07 August 2002 at 10:26 AM

Boolean operations are notoriously difficult for any package to perform (except Bryce, which doesn't actually do the geometry alterations, but rather just renders how the geometry would look if the boolean had been performed). That said, some packages handle booleans better than others. In my experience, there are all sorts of artifacts that come about from booleans. Here's a suggestion to minimize the artifacts. Before performing the boolean operation, make sure the surface fidelity of both objects is as high as it can possibly be. If you have built the objects in the Vertex modedler, you might subdivide the areas where they will intersect to give the program more places to calcualte the intersection, union or subtraction. (If built somehwere else, you could always convert the object to a vertex object; it'll wind up as a vertex object after the boolean operation, anyway.) I hope this is helpful. - Dex


AzChip posted Wed, 07 August 2002 at 10:28 AM

You could try exporting the object that's having the strange moire-esque pattern to another format -- say, DXF, and then re-imoprt it. There may be some strange Carrara-only thing that hangs on to the model after it's been booleaned. Just a thought.


Lugus posted Wed, 07 August 2002 at 12:25 PM

I have a similiar problem. If I try to Boolean subtract a scaled cylinder from a scaled sphere I get spurious vertices on the remaining sphere, and I'm not sure how to properly eliminate them at that point. If I go into the Model Room and delete them, the resulting sphere renders the removed vertices as notches where they would have been, and I'm not sure how to perform the Boolean operation without getting them in the first place. Anybody have any suggestions?

I've already send a bug report with detailed instructions on how to duplicate the problem to Eovia's "Bug Report" web page.

Regards,

Lugus