3D Faces...

[Nellie]

Hi Guys & Girls.

I'm in need of some advice regarding 3D faces.

I have a large ground area (surveyed and brought into CAD using LSS) made up of lots of 3D faces and need to create a polyline or something like it so i can slice a 3D model i have drawn (and extruded well below ground level) so i can show a true representation of where the ground meets the model/building.

The problem I have is none of the 3D faces are coplainar or on the same plain and can’t think of another way to do this.

I hope this makes sense.

Thanks in advance.

Nellie

[shift1313]

if you have a 3d face or surface mesh you can use surface-solid tool. 07-09 has this built in. You can also use the surface-solid autoLISP which will extrude your face in the Z direction so everything would be extruded in the same direction. The problem with this method is the resolution. It will split each "box" of the mesh in half and create triangled extrusions so your solid model will show this.

 

http://www.cadtutor.net/forum/showthread.php?t=1408

[Nellie]

Thanks shift313 but the surface i have is still lots of 3D faces and i can't seem to change them into anything else so i don't think the Lisp will work as its not a mesh YET.

 

Edgesurf is give this "Object not usable to define surface patch"

 

Any other advice would be most appriciated as this is really getting to me.

[rustysilo]

Can you upload the file?

[shift1313]

the edgesurf command will allow you to build a mesh surface from 4 closed polylines. Here is an example i just drew. I used 4 arcs.

 

 

while the lisp works on mesh faces, acad 07-09 has surface to solid build in. I dont know where it is on 2008 but i know its there.

[Nellie]

I was unable to upload the file due to limit of 250k But i have used a 3d polyline which has done the trick.

 

it's always the simple solutions that seem to be the answer.

 

Thanks again for your advice.