Modeling Tensile Membrane Structures

[MegaPixel]

Anticlastic Shape Reference:

http://www.cgarchitect.com/forum/filepush.asp?file=TensileMembrane.jpg

 

My Goal is to create a similar looking mesh to the Conical Shape shown above however there will be multiple peaks stitched together (Kind of like the Denver Int'l Airport Roof). I have very little experience with Patch modeling and Nurbs modeling and somehow I feel as if one of the two methods should do this for me. Could someone explain to me how they might go about creating this model? If I were creating one peak alone, I might just loft the Star like base to the Circular Peak and be done with it however since multiple peaks are now involved, I'm not so sure.

 

Thanks in advance for any suggestions.

[David Barbarash]

You should look into "soft-selection" in the help menu. Create your shape, extrude it, collapse to a patch or some kind of solid (if you're not planning on making changes to the form later, otherwise keep it an extruded spline) and subdivide it. Then using soft selection, just grab the center point and pull up in the Z direction. Then just delete the faces in the center of the cone you've just created to get the opening. Good luck with it and keep us posted!

 

David Barbarash

HM White Site Architects

Manhattan NY

[MegaPixel]

Thanks David. That sounds like a good suggestion for a single peak but what about doing a multi-peak shape?

I was just remembering the Landscape Modifier in VIZ where you could build terrain from the ground up using topo-lines. Do you think I should draw out my "Topo-Lines" for this multi-peak canopy and move them to their appropriate heights then create a surface for it when done?

I suppose at worse case, I could use your technique for one, then duplicate it and somehow weld them together...

[Chad Warner]

Mega-Pix-

Here is a VERY quick attempt at what David suggested doing with the soft selection. I think with a little bit more time, it could work. The only thing different that I did was add 3 circles to the line shape and made sure the interpolation steps on the curves of the line were set somewhat high (this will effect the number of points in the mesh) before I added the extrude modifier. After subdividing, I selected the points around the circles, and pulled them up with soft selection checked. The other thing you need to play with is the "Pinch" modifier. This will effect how the points are pulled up. I also played with rotating the selected circles to offset the towers a little bit, just to see. Hope it helps.

 

-Chad