17 replies to this topic

[simmsimaging]

I have a simple object but it is one that seems to defy easy UV'ing in 3DC:





If it wasn't bent it would be an easy cylindrical map in Max (or whatever) but with the bend it's very tricky to do without pelt mapping. I tried the various unwrap algorithms in 3DC but it always produces bad stretching on the two ends of the bent cylinders.

Unfold3D had some really good tools for dealing with this kind of shape: it would allow you to select a seam or row of edges and define it as "vertical' or "horizontal' and lock that edge and then reflow the UV's to align with it. That would, in this case, produce a nice long flat rectangle of UV's for the body of the cylinder.

3DC doesn't seem to have any capability for handling this - or am I missing something?

(I am aware I can just cut it up differently, but that precludes me from using the tiling textures I have for this part, and is beside the point anyway )

/b

[Psmith]

I can't see your attachment - can you repost it?


Greg Smith

[simmsimaging]

Sorry - can't seem to edit the post. Does this work better:

http://www.evernote....440a82bdb107265

[Tony Nemo]

Nope, I get an "access denied".

[simmsimaging]

sorry guys - hopefully this one works?

[Psmith]

Can't you just select those polygons at either end and scale and move them so they more approximately end up being the same size in the map?


Greg Smith

[simmsimaging]

Can't you just select those polygons at either end and scale and move them so they more approximately end up being the same size in the map?


Greg Smith

I suppose you could, but a bit easier said than done, particularly if you are concerned with keeping the Uv's fairly straight, and without a 'soft selection' kind of approach it would be pretty tedious no? The point in my mind is that the workflow advantages (speed/ease) kind of fall apart and I'd be better off UV'ing it somewhere else.

It's kind of a gap in what is otherwise I pretty good UV'g toolkit, at least to me.

b

[digman]

I'm not sure what is going on with the upwrapping on your pipes but I have an idea.

The curve pipes I tested unwrapped fine. I just used the default unwrapping of 3DCoat after selecting my seams. I chose one seam along the length of the pipes, also the ends of the pipes. I tested pipes, one with a close end and and another with open ends. In your picture it look like you follow the same seam selection.

The only thing I see from your image is the long elongated polygons on the ends of your pipes. They could be extreme coplaner polygons (a coplaner is a polygon that crosses more that one axis making it share a face with another polygon) and 3DCoat does not know which axis to unwrap them on correctly and you get stretching as result. That will happen in any program.

My pipes had more evenly spaced polygons reducing the chance of extreme co-planer polygons.
Test the pipes with more evenly space polygons and see if that works.

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[simmsimaging]

Thanks for looking at it digman. That didn't fix it for me though:




It might be something specific to the angle of the bend, dunno for sure. In any case, it's obviously not very controllable - the Unfold3D edge controls would really be a kick-ass addition and very useful for this kind of thing. Also very good for things like labels/decals - pretty much anywhere that you might need to unwrap, but still keep square edges.

/b

[digman]

Can you zip and upload the obj files so I can look at them...

[simmsimaging]

Sure - here is the obj:

http://www.simmsimag...handles.obj.zip (95.44 KB)

And here is what I got with 3DC in the last test:

http://www.simmsimag..._handles.3b.zip (324.82 KB

Thanks for taking a look.

b

[polyxo]

It indeed would be extremely helpful for all sorts of skinny islands to pin some border edges and then to force Unrolling into a rectangular domain with even polygon spread.

Headus UV-Layout does this automatically too - they demonstrate it on curled hair-strands which instead to some cork-screws can get unrolled to straight strips of polygons
for mapping a hair texture. Couldn't find that clip in a quick search though.

Edit: Found it. Here

[polyxo]

I tried the UV-Layout Demo on your file by following along the Video I posted.
A matter of seconds, really. Could not save though.

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[polyxo]

There's another thing which could work a lot better.
Selecting of UV-Borders on Geometry with mixed Quad and Tri Topology. Here selecting borders is very difficult.
Shift Click does not help here, one often needs to select each edge, one by one.

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[simmsimaging]

I tried the UV-Layout Demo on your file by following along the Video I posted.
A matter of seconds, really. Could not save though.

Yeah, that is exactly what Unfold3D did - and it only cost $1000 and crashed constantly The functionality is perfect though.

There's another thing which could work a lot better.
Selecting of UV-Borders on Geometry with mixed Quad and Tri Topology. Here selecting borders is very difficult.
Shift Click does not help here, one often needs to select each edge, one by one.

Agreed. Point to point seam selection (again like Unfold3D had) gets around this. I requested it a long time ago but only a few users got involved in the discussion - I don't think Andrew ever aknowledged it (that I remember anway) so don't know if it ever got considered.

[digman]

Here are the results of some testing. Some success but not quite good enough for your obj model.

Your obj, yes unwrapped strangely. I was able to get it to a rectangle in a few seconds using the edging tools but it did not remove the bad stretching that was in the first unwrapping. Edge tool location (Mark seams tab / select edges / edge tools appear left side of lower menu bar.)
Method I used. Select an edge, select edger, select edge loop and then select Horizontal or vertical depending upon my edge selections.

I had much better luck on a similar curve I created in Hexagon plus a really bendy one I also created. I used the same method as above after unwrapping.
I could use the brush tool to relax a few areas on the final rectangles without meshing up the outside straight edges. I did not do it in this case.

I would send your obj file to Andrew to see if he can figure out what is causing your obj to go bonkers in the unwrapping process. If it effects you, it effects others as well. Maybe it's how 3DCoat reads obj files created from different modeling programs, just a quess though. I also found a few small problems as well, possible bugs in the unwrapping area of 3DCoat.

The first two pictures are the final result of my curve models.
The second two pictures are the first unwrapping.
Your final rectangles are the last picture.

I can see areas in the unwrapping process that would be helpful to have as your suggestions have stated and I like to test to help solve problems plus find bugs. I hope this helps in some small way on your problem.

* a note. your uv island needs to be place horizontal across the uv space for the horizontal and vertical tool to work correctly or it seems that way...

If your want a free copy of the full version of Hexagon, Daz3D is giving it out till the end of April for free. Everyone has their modeler and Hexagon is mine for a number of years. Maybe you would want just to use to for testing purposes...

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[simmsimaging]

Hey Digman -
Thanks for checking this out.

I had tried the horizontal/vertical thing before but not with a full edge ring so it was only moving the one line of edges. It's *kinda* like what Unfold does, if you have a full selection of all horizontal or vertical edges, but doesn't have the tension/soft selection kind of effect that fixes stretching at the same time. I think that's why ultimately you still have problems on the ends. Still though - the way it works here is still going to be useful so thanks for that!

Regarding Hexagon: thanks for the tip. At this point I don't think the best answer is to add a new modeler into the pipeline though. I'd rather just find a good UV solution instead, but in this case too: the model is from stock so it's not like I would have built it anyway


The link to the 3DC file and the OBJ file are still in this post - hopefully Andrew will check it out.

[digman]

The tension/soft selection as you describe that fixes stretching would be a great feature request and fill out the uv functionally more... Maybe you could make one and I will bump it too...