Unwrapping / texturing a big cylinder
-
I need to texture a very big cylinder with a texture that is 4096 bytes wide. The cylinder has 32 segments. If I shrink the texture to 1024 pixels wide, so that I can use UV Tools cylindrical mapping, the texture is too blurry. I have therefore broken the texture into 4 equal sections. Problem is how to texture the cylinder accurately with it.
The solution I used was to break the cylinder into 4 quadrants with hard lines, remove each quadrant, flatten it out into a plane by rotating each of the 8 faces out flat, texturing the resulting rectangle, then painstakingly moving each surface back onto the cylinder and rotating it back into place.
So two questions. Is there anything like UV Tools that would do that automatically. If not, is there a plugin to flatten out a cylinder, then wrap it back up again please?
-
Can you share the texture and cylinder dimensions?
I use UV Tools Pro Beta to export the UVs as a .obj then opened in external mapping software.
Ultimate Unwrap 3D Pro is a good mapping tool that imports .skp.
-
I don't really want to export to other software. A plugin to explode the cylinder out to a flat plane (retaining all the hidden lines) is all I really need. I can then just apply the 4 textures to the 4 groups of 8 faces. I then need to wrap it all back up into a cylinder again. I did a few searches for such a plugin but was not sure what to search for.
The texture is 4096 x about 500 pixels high. The cylinder is 10.2m in diameter and 3.5m high.
-
The only plugin I know of then is Tgi3D Amorph. It has a Smart Texturing feature. It's $150 but has a 30day trial.
Or increase your texture so that's it's 4096 x 4096 and swap it out in the Entity Info box with this .skp
Or right click the texture in this .skp and edit in your image editor software and place your 4096 x 500 over the area I've marked.
-
Going on the premise that you want to stay within Sketchup, there is Jim Foltz' Unfold tool to try?
-
Flattery is another unfolding plugin.
-
You could try with my UVunwrap proof of concept plugin.
http://forums.sketchucation.com/viewtopic.php?f=180&t=39198&p=347129
(Note it's NOT working for advanced meshes. A cylinder would probably work with some manual editing. See tutorial movie clip for workflow.) -
Thanks a lot for the suggestions. I will give them a try and see how they go.
-
Don't understand the need for a plugin to wrap a texture on a cylinder. Use the texture tool.
-
@roger said:
Don't understand the need for a plugin to wrap a texture on a cylinder. Use the texture tool.
Could you elaborate please on how exactly one can use the texture tool to texture a 32-sided cylinder with 4 individual textures each 1024 bytes wide, such that the textures meet exactly at each intersection and wrap the cylinder completely.
-
It is simple and not too tedious. You set the cylinder to "show hidden geometry". You import an image and in the process click "use as texture". The image will come in and you attach it to one of the segments and size it vertically. When you let go, the texture will only paint one narrow segment. Then you take the eye dropper tool and sample the texture on the 1st segment and then paint the second segment, then you sample the second segment and paint the third segment and just keep repeating the process all the way around the cylinder. The texture will smoothley wrap all the way around as shown in my sample. When done unhide hidden geometry and lock the cylinder.
Unless I am missing something, that should be it.
-
I also have two systems for unwrapping a real world cylinder photographically if anyone needs a long strip photo of a column or vase so you can see all sides at once.
-
@roger said:
... Then you take the eye dropper tool and sample the texture on the 1st segment and then paint the second segment, then you sample the second segment and paint the third segment and just keep repeating the process all the way around the cylinder. The texture will smoothley wrap all the way around as shown in my sample. When done unhide hidden geometry and lock the cylinder.
Unless I am missing something, that should be it.
It would be nice if it was that simple but it is not. Each 1024-byte wide texture has to be painted on 8 segments. You take the first texture and paint it on the first segment, then sample and paint the next etc. When you get to the 8th segment there is no way that the texture will finish with pixel 1024 exactly at the final edge of the last segment. Not even vaguely close. You can repeat and repeat the process as much as you like, shrinking and enlarging the texture horizontally, and it will never match up exactly. Therein lies the problem.
It is even worse than that. Let's say the texture ends up too short. So you go back to the first segment and stretch the segment horizontally a bit. You then re-paint it on segment 2. It does not retain the same stretch. It reverts to the original horizontal width, so you can in fact never achieve the desired result by trial and error.
-
Take your texture and lay it out flat. Divide it into 8 segments. Sample each one with the paint tool and paint it onto the one panel of the column. Sample the next and the next and the next and paint each column individually. Post the column and the texture. I want to see for myself if failure is inevitable.
-
Unfortunately that that won't work either. When you sample each of the 8 segments you get the exact same texture each time.
-
Rather than guessing can I ask you to draw a 32-sided cylinder and try to manually paint 8 sides of it with any texture so the ends match up exactly with the ends of the 8 segments.
-
If you can adjust your texture resolution to match the cylinders face then it'll map. As long as both have the same height/width ratio. Otherwise your trying to fit a square map to cover a rectangular map.
-
Version 8 has a command called make texture unique. I just used it and it works.
-
Make texture unique reduces the quality of the texture badly and also shifts the texture several pixels left. It does not give a seamless result.
As for the suggestion of making the texture the same shape, that is impossible. Let's say the texture is 1024 pixels wide by 673 pixels high. Each segment of the cylinder is 1.3762m wide by 2.7643m high. What shape should I make the texture so it fits exactly?
-
Impossible....not really.
As your earlier request highlighted your requirement. Unfold the cylinders face, map it and fold up. So in essence your applying the texture to the flattened face so both match exactly.
If you look at my earlier .skp you'll see that I mapped a 4096x4096 texture to a cylinder without stretching or overlapping.
I can see your problem but your hampered by both SU'S mapping and your image canvas size.
Advertisement