Stacking UV's: Good practice or bad?

[Ryan93]

This is just a general modeling question but it applies specifically to a certain rolling stock item that I have been working on for quite some time. I have four identical corner 'sidesteps' on my model. I unwrapped one, then duplicated it three times so that all four have the same exact UV coordinates. You can see exactly what I'm talking about in the Image below. Is this considered to be a bad practice?

Texture question 1-5-16.JPG

I did it this way because I have many items that are similar and I felt that assigning each of them their own texture space would take up too much room. There are other objects that I have done this with as well (ladder rungs for example.) Are there any things I should look out for? Could this ultimately hinder a re-painter even if the shared UV's are of smaller 'detail' oriented Items?

I've still got a long way to go and much to learn. I've come to realize that all of the high detail work that I put into the bogeys (especially the springs) will need to be revised/re-done. At the time, I didn't realize the importance of vertex count and polys so going back to reduce poly count and re-map objects will be very time consuming.

I have not posted anything related to this model simply because my progress is very slow going at the moment and it could take upward of 4-6 more months to complete considering the limited amount of time I've had lately. I don't want anybody to get their hopes up too high. My original plan was to hold back on posting until I got all of the details, modelling, and textures completed. However, it will be much better to know if I'm doing things the wrong way now rather than later. I'd appreciate any and all feedback

[Chacal]

It depends on the specific part you are duplicating.
Mapping all 4 steps to the same coordinates means that any repaint for this car must have 4 similar steps.
This may not be a big hindrance. How many liveries for this car need different-colored steps? How many people would notice the discrepancy?
Probably not much.

BTW I appreciate that you are considering these questions. Too many assets are being published, especially official DLC, with automated UV mapping, completely disregarding the needs of repainters.

[Ryan93]

Thanks for the reply Chacal. I have tried to keep repainting in mind throughout this project. One example of this would be the ribs on the side of the body. I made the ribs and body one object and unwrapped it in such a way that any lettering will be conformed to the ribs themselves. To make it easier to understand, here are two pictures of what I'm talking about.

Main body Side UV layout Example.JPG

11-2 Woodchip hopper in game 1.JPG

This actually leads me to one more question. Is it generally better to have fewer individual objects- For example: How I modeled the side ribs with all vertices of the rib connected to the body like this:

Connected vertice example 1-5-16.JPG

Backside of connected rib for better understanding.JPG

OR would it be more efficient to have the ribs as separate objects. I combined the side ribs for the specific texture purposes, I'm just speaking in general terms. Like this rib located on the end (handbrake side) of the car:

not connected example 1-5-16.JPG

I guess to sum it up, Is it better to have more individual objects or fewer when you finish your model? Is it just the personal preference of each modeler? I'm not just talking about combining objects, I mean physically connecting the objects together as shown in pictures 3 and 4.
I hope I'm not being hard to understand or confusing anybody. I apologize for getting off topic, I'm just trying to gain as much knowledge as I can since this is the only time I have reached out for help with this project.

[harryadkins]

Looks good!

[Derek]

In the past I have almost always stacked UVs.
However I tend to take into account the liveries I have in mind before I do so.

Sometimes (but not always) you just have to please yourself rather than the reskinners.
Late at night when you are in unwrapping hell you do what needs to be done so you can get to bed!
:)

Note, however you do also have to take into account normal maps, that data does not like being mirrored and could look odd/lit wrong when used in different places.

[Chacal]

This actually leads me to one more question. Is it generally better to have fewer individual objects- For example: How I modeled the side ribs with all vertices of the rib connected to the body like this, OR would it be more efficient to have the ribs as separate objects. I guess to sum it up, Is it better to have more individual objects or fewer when you finish your model?

Fewer objects is better, IMO.
This will result in less vertices and less faces (not a big performance difference nowadays I know, but old habits die hard ** ).
More importantly, it is less likely that unsightly gaps will show in your model due to vertices not being perfectly aligned, especially after moving objects around.
Also less likely to have uncontrollable side effects such as z-fighting, moiré, etc.


** I used to develop for DOOM and Quake where every face counted -- we even made triangular ladder posts... Also, the BSP compiler did not like objects touching each other anywhere else than the edges -- it would split faces at the junction points, making a mess of triangles. Hence the habit of aligning vertices. Also, the editor and the compiler would sometimes make rounding errors, so that two objects that used to be perfectly aligned would suddenly have a gap, causing a "leak" that would CRASH THE WHOLE %$#%$ UNIVERSE I'm sorry it's been 20 years but I'm still pumped up.

[Ryan93]

Awesome, Thank you everyone for the professional advice and support.

Harry: Thank you!

Derek: I have not figured out normal maps and how to apply them in blender. I also don't know the naming or locations of the files required for normal maps but that's for another topic.
I know the feeling of modeling late at night. I usually have to go back a week later and fix my 2am mistakes.

Chacal: The concern about light showing through where the objects meet is exactly what prompted me to model the top rim (and other objects) as part of the body rather than separately.
It feels good to have some reassurance that I am on the right track (for the most part.)

Both of ya'lls replies made me chuckle