tented roof

[Phil hunt]

i have a project on the go at the moment....its a tricky one to model...the frameworks not to bad but i need to put a canvas roof over the tops of the

timber truss work

i have tried all the things that i know

revolve with rail

loft surfaces

have even tried duplicating the truss curve along a path and then lofting the surface but i can't seem to find an easy way of achieving the effect

[rDesign]

So Revolve with Rail didn't work if you break the trussed roof down into three (or more) sections, modeling the middle and two ends separately?

Thread on modeling tents that might be helpful: Tents

[Kaare Baekgaard]

I think you should take the hint and rethink the construction. The s-shaped trusses are structurally unsound and you are not using the tensile strength of the canvas, so it becomes dead weight and saggy to look at.

[Phil hunt]

hi kaare

this is an actual structure that exists and has been built many many times

its of a hire company but they don't have a 3d model which is my problem

[Phil hunt]

hi kaare

this is an actual structure that exists and has been built many many times

its of a hire company but they don't have a 3d model which is my problem

[Phil hunt]

hi kaare

this is an actual structure that exists and has been built many many times

its of a hire company but they don't have a 3d model which is my problem

[Phil hunt]

So Revolve with Rail didn't work if you break the trussed roof down into three (or more) sections, modelling the middle and two ends separately?

i think this will work i have tried this just need to spend some time on the project

thought i could do this in one move using the loft with 2 rails but seems to round the ends out and not keep the straight shape of the bottom rail

[rDesign]

Yeah - I think you'll have to break it apart into separate parts to model it correctly.

[Kaare Baekgaard]

My bad, Phil. In that case, maybe you can just extract nurbs curves from the top edges of the trusses and loft them with the 'ruled' setting on. Add solid the resulting surfaces, then select all of surfaces with the the shell solid tool to give the canvas a thickness.

[Benson Shaw]

Are there some points on each truss? Make NURBS curves as contours, several from top to bottom of the "roof" each curve hitting all the points on a certain elevation. Like site model contours. Then Loft Surface among the curves from bottom curve to top curve.

You could also try a Drape Surface. Not sure what will happen, but it might work.

-B

[Benson Shaw]

Well, tried to drape the ribs. Not good.

Try what Kaare said except no need to add solid & shell (but ok if you want):

Extract an edge from the truss, or both top edges, then Loft Surface>Ruled all the way around. My example only did half way around. This creates a group of Nurbs Surfaces with V degree=2 and U degree=1. To get the sag between the ribs, enter the group, select one of the surfaces (my red one) and in OIP change the U degree to 2. Then change the Move option to U vertices, and use the edit arrows to select a middle vertex. Now in the xyz position fields, add 6" (eg) to the y value and a sag will appear. Repeat for each surface. Gets tricky for the ones on the curved ends of the tent, but rotate the surface so that plan projection is parallel to x axis, add the value to the U vertices, then rotate the surface back into position.

Another way - Extrude along path works ok. Profile is edge of one of the trusses. Path is ground plane footprint. No dips between the ribs, so not super realistic, but it does make a cover.

-B

Edited July 18, 2015 by Benson Shaw

[Kevin McAllister]

Great explanation Benson!

KM

[Benson Shaw]

Thanks, Kevin

Adding that in my example, long axis of the tent is parallel to x axis of the layer plane.

-B

[AlanW]

Benson,

Could you run a short video on what you did as it will be much easier to follow step by step what you did and maybe add to a youtube channel?

I can follow what you did but the video really helps.

If you don't have a screen capture program Powerpoint (Under insert Media) has one attached that can record screen and audio.

Thanks.

[Phil hunt]

wow this is good

agreed a you tube video would be good if possible

i cant seem to get the hang of this yet

(To get the sag between the ribs, enter the group, select one of the surfaces (my red one) and in OIP change the U degree to 2. Then change the Move option to U vertices, and use the edit arrows to select a middle vertex. Now in the xyz position fields, add 6" (eg) to the y value and a sag will appear. Repeat for each surface. Gets tricky for the ones on the curved ends of the tent, but rotate the surface so that plan projection is parallel to x axis, add the value to the U vertices, then rotate the surface back into position.)

but this is a get of jail solution to at least give me a roof over the tent

i think it would be good for VW to put dome videos up regarding extracting and

lofting as i am sure a lot of users just give up and really its in the software all the time

thanks all

[Benson Shaw]

Here's a link to video tutorial (Vimeo) on this question. May have to turn up the sound a bit.

One item I did not elaborate in the video:

When one of the NURBS surfaces is selected to make the sag, open the OIP pulldown for Move and select U Vertices.

Post back with questions.

-B

[Phil hunt]

brilliant video benson.....very good....and thanks for taking the time to post this.....this i can use on a lot of my projects

regards

phil

[Markvl]

Excellent short video Benson. Thanks for sharing that. Thanks Phil for posting your problem and to the others for your input into solving the problem. Love this Forum.

[Phil hunt]

Had a problem with duplicating along a path

In bensons video he duplicated the nurbs curve around what's best to describe as a running track however on my posted screen shot it has faceted end so when I tried this method it resulted in a weird outcome.....I will post a screenshot tomorrow......

[Benson Shaw]

Phil, you'll get there. Going back to images in your first post of this thread, it looks like you have the frame modeled. I used DAP because that was a fast way to distribute a bunch of profiles to demo the loft surface and adding some simple deflection/sag. You don't need to use DAP.

Instead, trace each profile with the NURBS Curve tool and place on the foot print to match truss location and rotation. OR extract (3d Tool Set>Extract Tool>Extract Edge mode) one (or both) of the top edges of the trusses and leave them in place. Convert them to NURBS if they extract as polylines. You only need to extract a quarter of them, then mirror as needed to get enough to loft half the tent. Or lofting a quarter tent might work. Loft the S curved center area separately from the flatter outer area.

Also, a refinement of the sag: If the actual tent has no sag or deflection at ground or at that top oval oculus, then don't move the entire U column of a surface. Make the U degree 2, but set the OIP Move field to Vertex Only and use the arrow keys to select a vertex and adjust the value of the z field. Make deflection where its found in the real tent - pulled by stakes? gravity? draped over cables or other elements?

OK, keep posting. Show some of your screenshots as you try things.

-B

[Phil hunt]

i tried the duplicate along path and this is the outcome see screenshots

[Phil hunt]

this was the final outcome but had to copy the nurbs curves manually

[Phil hunt]

this is the interior needs a bit more work to align all the decorative steelwork

but at least i am able to work on the project interior

[Benson Shaw]

Yes, DAP needs some finesse. I think it has some bugs. Sometimes reverse the path direction or mirror the profile to opposite side of path, or split the path into halves or quarters. But manual placement is best way for your project.

-B

[Benson Shaw]

Final interior image shows this is getting really complete! Lookin' good.

A couple of the ends of S trusses are visible poking through the beams near center of the image. Solution is to move them or redraw draw them, then loft again.

It's essential to organize all these components with classes and layers so the various items can be isolated for edit.

-B