bit of a modelling challenge

[Anonymous]

hi

a workmate has asked me how to model something.

If you look at the attached pic the hoops are like irregular sized hooped beams and the red line indicates that we want to put a 'roof' mesh on to the underlying hoops. sort of like shrink wrapping round the structure.

[attachment=33165:Picture_1.jpg]

anyone got any ideas?

TIA

Adri

[Anonymous]

Hello Adri,
I think the first thing to do is model the hooped beams using TrussMaker.
Are these hooped beams circular arcs or elliptical arcs or some other shape ?
To make the mesh roof, I would use a surface only mesh (no skirt)
with a regular arrangement of independent nodes. To get the correct
arc for the sag between the beams I think you will need Frank Beister's
catenary object. His object can draw a parabola curve as well and has
plenty of 3d hotspots so you can drag the mesh nodes up to
the curve in the 3D window. Please see this thread.

http://archicad-talk.graphisoft.com/viewtopic.php?p=43398&highlight=catenary#43398

The problem I see is that TrussMaker does not have 3d hotspots
so you will have to do your best in the 3D window to get the mesh
to lay along the surface of the beams.
If the hooped beam arcs are circular or elliptical, I have made
an object that has 3d hotspots arrayed along a circular or elliptical
arc made specifically for editing meshes in 3D and you are
welcome to it.
Peter Devlin

[Djordje]

You are probably not familiar with COONS?

ArchiForma, MaxonForm, SketchUp

[Anonymous]

Hello Djordje,
If Adri knows GDL she could try COONS but I don't think COONS
will make the right shape because COONS uses an internal
algorithm to interpolate the the points defining the surface
within the the four edges and those points cannot be directly
edited and do not necessarily define a surface that is correct.
I do not know what that internal algorithm is so I don' know
how to define the four edges so that the surface is correct.
Do you ?
Peter Devlin

[Anonymous]

Peter,

If you have the object it'd be nice to have a play with it. I'm not used to using 3d hotspots so it'll be instructive to have a go.

Cheers

Adri

[Anonymous]

Adri,
I will need your e-mail address
and your AC version.
Peter Devlin

[Anonymous]

Myself I have build the frame as alot of "Complex profiles"
But the profile won't be a cut through a beam, it would be the beam from start to end and the lenght of beam (when you are drawing it) are the with of it.

[Anonymous]

Hello Tobias,
An excellent idea !!!
It solves the problem of 3d hotspots because you
can array 2d hotspots along the edge of the fill
in the complex profile editor and they are converted
to 3d hotspots and show when the wall/beam is selected in 3D.
Thanks,
Peter Devlin