solid void errors

[kafka]

Hi All,

Im trying to model this geometry like the small image you can see in the attached image. It is a pentagon solid estrusion cut with simple arch void extrusion on each side of the pentagon...
The problem is that I cannot complete the solid as I get an error saying "cannot keep element joined together - disjoin them"! Then of course If I disjoin the two remaining voids I cannot complete my component as those voids are not intersecting my solid..

Why this bizarre behaviour? what am I doing wrong?

Attached is also the revit file.

Marco

[Scott D Davis]

The way Revit handles void geometry, it wont let you take the 5 void arches from the faces and have them meet "perfectly" at the middle of the hexagon. If you pass the voids over this halfway point, or even get really close, then Revit starts having issues with the way the voids are "competing" to cut out the last portion. One void can cut it, but as soon as any of the other 4 try to cut the same solid, Revit throws up errors. Basically its expecting to cut a piece of solid, and then the solid isn't there. The solution is to get the voids really close to the center, then use a small void hexagon to cut out the remaining "leg" at the center of the geometry. Hope that explains it. I have an example i can post if you need it.

[kafka]

Hi Scott,

thank you very much for this. So in order to avoid errors should I always avoid to meet multiple edges together in solid/void operation? As suggested in the book "Mastering Revit Architecture 2010" I thought it was possible to perform a kind o boolean operation with the cut geometry tool...but maybe not...
I hope this will work with new features in Revit2011.

Best,

Marco

[arqt49]

One option is not to model one extruded pentagon and cut it 5 times.
Model 5 slices and cut each one. Then, join them.
You have to do more modelling, but you won't get that error message.
I don't believe 2011 will solve this issue.

[kafka]

Hi Gonçalo,

good idea actually! modelling steps can be reduced quite easily using an array I guess..
thank you!