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Workflow: Retopo->UDIM-ready UVs->Export Bake for PPP?


philbraaten
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Go to solution Solved by ajz3d,

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Hi, everyone, first post here though I wouldn't say I'm exactly a new user. I've been using 3D Coat off and on for the better part of this year, and while I've been able to get most of my questions answered viewing many of the videos that have been made, I've been extremely stumped on this one particular issue: 

 

How to bake out UDIM UV sets from the retopo room.

 

So many invisible walls with this one it seems... I can create PLENTY of new UV sets inside the retopo room and place unwrapped islands into any UV set I create... this part is easy and obvious. The issue is when I bake for PPP (non-displace/normal baking) and choose "UV MAP TYPING: KEEP UV", It collapses all the UV sets back into the default UV set completely ignoring the other UV sets I've made. What's the "correct" way of preserving each UV set? 

 

The only workaround I've been able to come up with, is to move each UV set that isn't 1001/default to the next available UV space. When I do this, the bake works fine and I can see the UV sets I've moved out in the UV set list in the paint/UV rooms. 

 

Only problem: 1) if two UV sets occupy the same UDIM/UV space, those get collapsed into it's corresponding UDIM set when baked from Retopo, and 2) it's becomes difficult to determine the area of each UV quadrant boundary after the immediate top/bottom/L/R spaces are filled. 2 quadrants in any direction and it becomes difficult to 'guess' if you've hit a border or not. 

 

So my question to the forum is, what is the best way to preserve UV sets when baking out of the retopo room? Is there a numeric U/V value input when transforming islands within the Retopo UV toolset so there's precision with placement?

 

It may seem trivial but we rely on UDIM-based UVs for our pipeline and it just seems to me that I'm missing a critical workflow process/step or something and it would save me a lot of time if laying out of each UVset happened the way I would assume it should. I appreciate any feedback anyone has on the subject. Thanks!

 

 

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Hi.

This is definitely not normal. A few questions:

1. Which version of 3D-Coat do you have installed?

2. Does 3D-Coat collapse your UV-sets right after you choose Keep UV from the dropdown list in the Import Object for PPP window or do you still have those UV-sets once you choose the Keep UV item, but they get merged once you press the OK button and inspect the results in the paint room?

3. Do you unwrap your retopo groups inside retopo room or do you import (to retopo room) objects that are already unwrapped into multiple UV-tiles?

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Hi.

This is definitely not normal. A few questions:

1. Which version of 3D-Coat do you have installed?

2. Does 3D-Coat collapse your UV-sets right after you choose Keep UV from the dropdown list in the Import Object for PPP window or do you still have those UV-sets once you choose the Keep UV item, but they get merged once you press the OK button and inspect the results in the paint room?

3. Do you unwrap your retopo groups inside retopo room or do you import (to retopo room) objects that are already unwrapped into multiple UV-tiles?

1: I'm currently on the most recent (as of this morning) build: 4.5.23, but I noticed this back from 5.19 IIRC. I've been using 3DC since 4.0.19 and have used 4.5 since beta 12, I think. 

2. I don't 'import' the object, but within Retopo room I choose "Bake>Retopo->per pixel" (no baking) to create the polygonal mesh with UVs for PPP in the paint room. When the dialog box appears, I do indeed select choose "Keep UVs", along with "Import Tiles as UV Sets" and the dialog box shows me all the UV Sets that I currently have created in the Retopo room. 

3. This is the first time I've tried to unwrap while re-topologizing. Objects/models created outside of 3DC have been imported directly for UVs/Painting and this has not been an issue. 

 

I can of course export the mesh, and then re-import it and bring it into the UV room and create UV Sets there. UV Sets created there have worked in the past. It's just the anomaly of unwrapping while in the retopo room and designating different UV sets inside the retopo room that doesn't get created when choosing "Bake>Retopo->per pixel (no baking)"

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Try clearing the "Import Tiles as UV Sets" flag. This flag is only useful for geometry that you import to retopo room and which already has UV islands already distributed between multiple UDIM tiles.

The thing is that 3D-Coat does not directly support UVs outside of the base 1001 tile, so everything gets unwrapped inside this base tile. What the Import Tiles as UV-sets flag does, is it looks for UV islands in 1001, 1002, 1003, etc., and if it finds them, it places them in appropriate UV-sets. You said that this is the first time you have unwrapped your model inside retopo room. This means that all of your UV-sets are inside 1001. So if you select the Import Tiles as UV-sets, then 3D-Coat will not find any UV islands outside of 1001 and thus will throw all of the islands into one UV-set.

Clear this flag and try again.

 

Once your objects land in the paint room, you'll find your multiple UV-sets there, as well as multiple surface materials. At this point all of the UV-sets are on separate 1001 tiles (for each material), but don't worry. Once you're done with texturing, and choose to Export Model and Textures, you'll be presented with an export window where you will be able to select the Export UV Sets as Tiles. By enabling this flag all of your UV-sets will be put into separate UDIM tiles.

There's a caveat though. Several versions ago the UDIM order was pretty much random, but it might have changed in one of the most recent versions. It is highly possible that you'll have to rename your exported files a bit, and reorder your UDIM tiles in a 3rd party program.

 

---

EDIT: Some typos.

Edited by ajz3d
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That seems to have fixed it! (I only tried with a simple object, 2 UV sets but works as expected)... 

 

I understand the issue surrounding UV sets in 3D Coat and I do know that each UV set originates at U0 V0... for me this was never an issue. Also, we know all about re-naming the UDIM numbers, so we're aware of that as well.

 

I guess it was as simple as disabling the "Import tiles as UV sets" flag, thanks again!

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