Tensile Structure / Circus Tent

[GSP_nowhere]

Hello everyone!

I wanted to ask if anyone has a clue on how to approach these kind of structures in regards of Nurbs-Modelling ?
What would be a good approach / plan of attack to model these kinds of structures, especially the fabric?




I have tried a few approaches with building wireframes via nurbs-curves and trying to loft these. Allthough my results havent been neither accurate nor pleasing.
I end up with many sub-surfaces which in the end dont blend well with each other. They have a rather sharp edge where they are beeing stitched.

I have also tried approaching this task with the subdivsion tool. I get pretty close, but upon converting the subdivision to Nurbs you cant stich the surfaces together anymore hence not make a solid out of the surfaces with the shell tool.

does anybody have an Idea on how to go about this kind of task?

Thank you in advance!

Greetings

Edited May 15, 2024 by GSP_nowhere

[rDesign]

It sounds like you’ve already tried most of the suggested approaches. A search of the forums for the word “tent” will give a bunch of results where others have tried to approach the same problem with varying degrees of success.

 

Here are links to several of the more recent threads:

 

Edited May 15, 2024 by rDesign

[GSP_nowhere]

@rDesign

thank you for the suggestion, ill look into it further
Thank you

[bcd]

@VIRTUALENVIRONS  - did someone say nurbs? 😀

[VIRTUALENVIRONS]

41 minutes ago, bcd said:

did someone say nurbs?

Yes bcd, I think I read that somewhere in this post..😀

 

 

[GSP_nowhere]

Thank you for the suggestions and the Video @VIRTUALENVIRONS !
That looks pretty good! 🙂

ill have another try on this !

Greetings

[Mr. Minus]

Hey i am having trouble making the tent roof for this tent, i need the inside of the roof for lighting design... please helt... i'm in a hurry

Ørsted 46x78 3D.vwx

[VIRTUALENVIRONS]

Is this the tent you are trying to make or something similar.

 

 

[Mr. Minus]

Yes almost 

[VIRTUALENVIRONS]

How accurate does this have to be?  Are you placing rigging structures, trusses, seating inside that have to have the correct clearance or just for light purposes.

[Mr. Minus]

Mostly Light, but i have a big rig on the inside, so it cant be of to much 

 

[VIRTUALENVIRONS]

This is a significant project in terms of modelling, but doable.  It is difficult to advise further without seeing the top, front and Side dimensions.  Like below.

 

 

 

[Mr. Minus]

I am this fare now, how do i close all the holes?

Big Tent.vwx

[VIRTUALENVIRONS]

 

[Mr. Minus]

Is ther a way to close all the air gaps? 🤔

 

 

 

[VIRTUALENVIRONS]

Although not exactly sure of the method you used (Good work though), it appears you went a polygon route, which may be giving you those fine gaps.

 

You may have to live with them.

 

But, when you render that same section (bottom image) in better quality Renderworks......does it go away.

[Mr. Minus]

No 🤨

[Mr. Minus]

I used Loft surface tool

 

[VIRTUALENVIRONS]

1 hour ago, Mr. Minus said:

I used Loft surface tool

Good Stuff, nice job.  One of the things I have noticed is that if you extract a curve from a surface and loft it, It does not necessarily fit properly.  If you can make a joint using the same curve(s), it seems better.

 

Anyway very nice work.

[Mr. Minus]

Final version for now

[VIRTUALENVIRONS]

Excellent.  Looks great.  

[Claes Lundstrom]

I may be wrong, but it looks like you have a problem with drainage. It's never a good idea to have completely flat areas, as it may cause huge water collecting areas in fabrics structures. Panels look a bit bumpy too, but it could be the rendering. I use cross section curves to fair the shape, which can be done in VW, even though it's rather tedious since you don't have dynamic cross sectioning. Also, have you analyzed the panel layout, so that each panel fits into a given material width, and having a minimum of waste ? Using NURBs can be a problem, as they can cause misalignments between panel edges, and this can cause a lot of problems. Having matching panel lengths and alignment marks guarantees a good panel assembly, in my experience.

[VIRTUALENVIRONS]

@Claes Lundstrom  Hi Claes.  He is only looking for interior lighting design and not structural accuracy, so this will likely work for him.  

 

Yes, when it comes to large event tents with multiple posts, NURBS curves are not the solution.   I use NURBS surfaces.  The project below to construct an accurate event tent came to me "apres Rhino and Blender people".  There is a picture of this tent earlier in the thread.

 

The model had to be very accurate as seating and structural devices needed to be placed inside.  The YouTube video I show above that is similar, is not this tent.  I made that as a demo, but there requirements went further.  The transition from circular to flat panels was proving more difficult than they anticipated.  Also, different colours for outside and inside.

 

I developed a continuous NURBS surface that I could manipulate.  The panel seems show in purple are just parametric extraction.

 

 

 

[Claes Lundstrom]

2 hours ago, VIRTUALENVIRONS said:

@Claes Lundstrom  Hi Claes.  He is only looking for interior lighting design and not structural accuracy, so this will likely work for him.  

 

Yes, when it comes to large event tents with multiple posts, NURBS curves are not the solution.   I use NURBS surfaces.  The project below to construct an accurate event tent came to me "apres Rhino and Blender people".  There is a picture of this tent earlier in the thread.

 

The model had to be very accurate as seating and structural devices needed to be placed inside.  The YouTube video I show above that is similar, is not this tent.  I made that as a demo, but there requirements went further.  The transition from circular to flat panels was proving more difficult than they anticipated.  Also, different colours for outside and inside.

 

I developed a continuous NURBS surface that I could manipulate.  The panel seems show in purple are just parametric extraction.

 

 

 

 

 I have done a fair number of real production designs of these types of very large tents, but to be honest, I never use VW for these jobs. I have also received designs from some of the specialized apps for these jobs, and I can't say that I'm all that impressed with what they have delivered. Quite often, these models need more cleaning up work than it takes to model it from scratch.