How to apply an image to a curved poly surface - photo backdrop backing

[Michael_Hersey]

Hello,

I work in film / tv in regards to set design. Often times we will model a house set and need to show what our photo backdrops will look like when we export model views. The backdrop has 2 15’ radius curves on each end and a flat / planar section in the middle. Im trying UV mapping, flow along surface, decals etc and I cant seem to get it to land right. Ive been gradually switching from sketchup to Rhino and this is something I have done SKP. Curious if there are any tutorials on this? Im not sure if planar or cylindrical is best suited for this as my surface contains elements of both. Backdrop size is 100’ x 20’ & my surface has 2 15’ radiused corners.

Any help greatly appreciated! I’ve been scouring YouTube for half a day now.

[maje90 (Riccardo Majewski)]

Your problem is because that is a polysurface, you need a single surface.

Create the base curve arc-line-arc as a single curve, rebuild it with a high point count.
Then extrude it to a single surface.
Apply your texture.

… but it depends if you wanted a “unrolled” or a “projected” result.

[davidcockey]

To create a single surface with curved ends:
Create a line with curved ends.
Explode the curve.
Join the individual curves into a single curve.
ExtrudeCrv with SplitAtTangents=No
Result should be a single surface.

Create the surface with curved ends as a single surface.
UnrollSrfUV (not UnrollSrf) to unroll the surface. UnrollSrfUV will unroll the single surface with curved ends as a single surface.
Picture with the desired image.
Scale the picture to desired size.
Move the picture to desired location on the unrolled surface
FlowAlongSrf

[encephalon]

i would just duplicate the upper curves join them and use Flow it will act like a curtain. FlowAlongSrf is also an option but in that case Flow might be a bit easier.

[BrianJ (Brian James)]

Hi @Michael_Hersey ,

I’d use ‘Unwrap’ and then adjust the UVs for the polysrf in the ‘UVeditor’ after applying the material with the texture map.

Curved_backplate.3dm (4.9 MB)

If you can share the 3dm, I’ll take a look at unwrapping the polysrf’s UVs to do this with your file too.

[encephalon]

i also must add, since the quater circles are tangend to the line, if you join the curves to one single curve before you extrude it, it actually makes a single surface already.

[jeremy5 (Jeremy)]

@encephalon

if you join the curves to one single curve before you extrude it, it actually makes a single surface already

Only if you have set SplitAtTangents=No as @davidcockey says above. You may have this set or not - Rhino remembers the last used setting.

And AFAIK the gumball extrude always uses SplitAtTangents=Yes, regardless of the command option. Maybe that is something that should change.