What would be the best approach/method to take an bitmap image or vector image (via Inkscape) and place it on a surface of sphere? I don’t know ‘what to read’ or ‘search’ for to accomplish this in Rhino. I found a few Blender tutors using UV mapping but no Rhino sphere ‘tutors’. Ideally I want to model say a 30" steel sphere with a graphical scene on it, be able to adjust (scale/move etc.) the image on the sphere and eventually ‘maybe’ make a template to transfer to the surface of the sphere so I can cut out the image.
Hello - for an image, I think I’d use a Decal and Rendered display mode. For curves it’s trickier - there are several ways to get curves onto surfaces, -
Pull, Project, FlowAlongSrf, ApplyCrv… any or all all might be useful depending on just what sort of control you need.
… you’ll probably find this hard to believe, but I can’t find any specific directions (like ‘help’) on using the ‘decal’ command and it’s sub-command prompts (Version 6). I tried typing in decal in the command help box with no luck. Haven’t seen any tutors either.
I was able to get an image on the surface of a sphere but that’s about it. I haven’t a clue how to manipulate (scale, move it, prevent distortion etc.) the image unless it’s supposed to be done with all the decal sub-command prompts.
Yes it’s a little hard to find the help on this one
It’s also under the properties panel help topic.
As you’ve no doubt discovered, creating textures for spherical mapping is not trivial.
Your workflow is going to depend a lot on what final output you require.
For example are you just wanting to map a texture to a sphere for visualization/rendering?
Or maybe create cutting patterns for plate steel that will then be bent and welded?
I tried that before posting my original question. Help -> Help Topics - Decal and saw 51 hits but none specifically about decal and the sub-commands. I also tried the Properties panel with no success.
I was hoping for two outcomes.
First to model a particular overall design (bitmap or vector) or a series of much smaller individual designs, place them on the surface of the sphere, then render for visual purposes. It would be even nicer if I could extrude those designs and subtract them from the sphere too.
Second, if possible to generate a template of that design so I can trace it on a steel sphere.
I make ‘things like this’ on the side and was hoping to model them first to see if they’re visually appealing, then cut them out with oxygen acetylene torch.
The help topic is definitely there. However i don’t think decals is going to be the solution.
Since you only want line art, try the following.
The hardest part is dealing with the pinching at the poles.
One way to deal with that is to work on a bitmap cubic map and then convert that to an equirectangular texture. Then trace that to get the line art. There are a few free online cube to equirectangular converters out there.
Or if you do a lot of this then I recommend Flaming Pears Flexify 2 plugin for Photoshop.
Hope that helps, Steve
Thanks for the help and suggestions. On another note, IF this is what you’re talking about, when I click on Help then command help and type in Decal I see nothing.
So there more than likely there is no method for me to simulate the cut sphere that I posted above in Rhino? Meaning to actually Boolean a extruded image (or a series of smaller extruded images placed on the surface) then subtract it from the sphere which has a wall thickness, then render it with a material. I suppose the point is I wanted a customer to see what the final product would look like before I physically make it.
Generating a pattern or template was just on a wish list.
Thanks again …
Hello - There is a way but you’ll have to contend with the distortion of the curves from flat - rectangular - to spherical, = pinched at the poles, as Steve mentioned. One way is to
FlowAlongSrf the curves using History and distort the base surface or the original curve, to compensate. it will be hard to get it right…
CurvesToSphere.3dm (125.2 KB)
I figured out how to use the decal command, thanks. Is it possible to place a SVG file on a surface? I did try FlowAlongSrf without success. If so, can it be extruded too then use a boolean difference? Oops, I did get ApplyCrv to work on the SVG, at least somewhat (see image below). At least it’s on the surface even though it’s heavily distorted. Sorry for wasting everyone(s) time.
SVGtest.3dm (1.1 MB)