When To Use What Uv Size.

[nachtai]

Hello Everyone,

I am still on my journey in learning the best practices for meshing in Secondlife. While browsing through the forums I see a lot of people complaining about the overuse of 1024 x 1024 sized textures. I can understand this as this is a large size image to have to generate and if everything is at 1k size, then this makes a heavy object/clothing. My question is, when would you suggest using 1k uv sizes over say a 512 or smaller?

Thank you for any answers.

[Chic Aeon]

I am sure that each creator will have their own answer. For ME, I typically use a 1024 texture for a single piece of furniture. A more complex piece of furniture might take two  1024s but that isn't the norm for me.    A smallish house could take  maybe four?   While people do complain about 1024 textures, it is often that people are using a MULTITUDE of 1024 textures on one mesh object (not a house :D).  Unfortunately what happens when you try using a 512 texture on say a dresser or chest fore example, the texture is not sharp at all -- no matter the resolution it was baked at. Then no one will buy it or use it. 

 

So you have to decide what works for YOU.

 

[Da5id Weatherwax]

Chic is exactly correct. The size to use is "the smallest size that looks right" - this will vary depending on your design. Test 'em, either on the beta grid or with a viewer that lets you use local textures. Try the different resolutions and when you hit a level where you think "no, I can't use that", use the next higher one. Also remember that you don't have to use square textures. There are situations where it makes much more sense to lay out your UV map planning on (for example) a 1024x128 or a 512x256

[Kyrah Abattoir]

On a lot of projects, if the unwrapping tend to create a few "long" uv sections, it's not a bad idea to assume this section will be 1024px long, then you can arrange all the other UV islands as tightly as you can at the same resolution and see how much you actually need: 1024x1024? 1024x512? 1024x256? less?

[Beq Janus]

To drive home the "it depends" with an example; a single fully utilised 1024x1024 is typically preferable over 4 separate (equally populated) 512x512s (which give you the same pixel real estate) however in practice you may want to separate out textures onto different mesh faces to facilitate colour variations or other such customisations. 

Consider the furniture example from Chic perhaps, it really depends on how you expect the product to be used. I could use a single baked 1024x512 because I know that the product is to be present in a fixed set of configurations, but I might equally split it and have a 512 of wood/metal trims and cushions alongside a 512 for the rest of the upholstery, this gives me a little more flexibility and arguably gets better reuse. Imagine a scene where I  have two or more armchairs with the same upholstery but different cushions (nobody ever said I had good taste 😉 ). In this case the viewer would be able to reuse the common upholstery texture shared between the armchairs in the scene and only have to deal with the two smaller "differences" compared to a single bake of a a 1024x512 which would require a new (unique) texture download for each variant.  Note too that due to the way things are rendered it is good practice to ensure that any transparency is kept on a separate texture face to things which are fully opaque.

The thing to avoid, and where the common cry over excessive texture load comes from, is using a higher resolution texture where it is never (or rarely) going to be seen and/or wasting space in a UV map so that you need two texture sheets where with a little bit of packing you could have achieved one.

My favourite (bad) example is a nipple ring I own that is plain gold. it has a 1024x1024 "gold" texture, plus a blank 1024x1024 normal map (required only for the alpha channel) and a 1024x1024 specular map. all of this in an item that is little more than a few centimetres in size and (with a few exceptions) is not going to get more than a passing glance at the best of times. 

 

 

 

Edited March 19, 2020 by Beq Janus

[Chic Aeon]

1 hour ago, Beq Janus said:

The thing to avoid, and where the common cry over excessive texture load comes from, is using a higher resolution texture where it is never (or rarely) going to be seen and/or wasting space in a UV map so that you need two texture sheets where with a little bit of packing you could have achieved one.

My favourite (bad) example is a nipple ring I own that is plain gold. it has a 1024x1024 "gold" texture, plus a blank 1024x1024 normal map (required only for the alpha channel) and a 1024x1024 specular map. all of this in an item that is little more than a few centimetres in size and (with a few exceptions) is not going to get more than a passing glance at the best of times. 

Here is a visual example of using several materials in one 1024 texture (mostly for the OP :D).  I always make my UV maps by hand and "don't" use the packing feature in Blender as I frequently do touch ups in my graphics program and really like to be able to find the different pieces easily.   This texture goes on the one piece mesh model as shown.

 

I have actually found some smallish FOOD decor that was a million triangles (OMG) and today I found a very cute pigeon coop with pigeons (small).  I was going to buy it until I saw that just the coop and two birds weighed in at half a million triangles.  So it IS GOOD TO REMEMBER TO CHECK before purchasing LOL. 

 

The dual planter with plants is one land impact and good sized :D.   

[Kyrah Abattoir]

@Chic Aeon In your example I see a lot of duplicates, or near duplicates:

• The 4 "pot window" sections could share area, and that would avoid having them at an angle.
• The plant leaves could probably share texture too, you have 10 unique leaves and no one would notive repetition there.
• Top right & bottom left wood show lots of duplication.

Personally I wouldn't have baked the wood at all, I'd have used a single small repeatable texture, rotated UV islands to change grain direction, and maybe used an extra "face/material" or two on the mesh to be able to darken a few of the wood sections/inner/undersides with the in-world tinting tool to provide a little bit of contrast at no cost.

[Wulfie Reanimator]

One good indicator for texture size would be to ask yourself "how big is this object, and how much space is it expected to take on the screen?"

Imagine a simple textured globe. All sides are equally important because you're expecting it to be inspected from any angle and the user can only see half of the texture at any time, so you might need a larger texture.

Another example is the inside of a room/building. The walls and floors have large, clearly visible surface areas and they'll cover most of the user's screen in most cases. Large textures are definitely justified there.

Then there's small items like jewelry. There might be a lot of surfaces, but they are very small. Here's an actual example:

This how close I typically get to my own avatar when I want to just look at it. At this distance, the largest pearls are about 12 pixels on the screen... not much detail to see. You can get away with a much smaller texture. It's common for creators to UV unwrap a model like this so that each pearl is individually laid out on the UV, but they could all share the same spot and have identical texture. The pearls above look identical to begin with, so nothing would be lost. Basically, this necklace has two components: pearls, and the links between. You could use a 128 texture instead of the 1024 the above actually uses without losing any detail or even gaining more detail.

And for reference: The picture above is 730x730. If you were to use a 512 texture for those pearls, try to imagine how much space on that texture is wasted because your texture is crammed into such a small space. (I counted, there are ~200 pearls in view, totaling about 10% of a 512 texture in pixels.)

Edited March 19, 2020 by Wulfie Reanimator

[Da5id Weatherwax]

I can give another example - not a particularly good one because it is still a WIP but it's showing what you can do with minimal texturing and the right maps.

 

This is a full tournament-size snooker table at 1:1 scale. It uses three 512x512 textures. a diffuse and normal for the wooden parts and one for the line markings on the table surface. Every other "face" of the model is a tinted blank texture for every place it needs a "map", letting the SL lighting make it "degrade gracefully" for lower graphics settings. Images were taken with the official viewer at each preset level, no post apart from adding the text and combining them into frames of a gif, no fancy tricks with a high-graphics viewer like Black Dragon The table LODs gracefully and has a LI of 35, not including the balls, each of which is a separate entity.

[nachtai]

I really do thank everyone for all of the responses! I come from creating for a game that only uses one UV per item/clothing and it has to be box sized so it's limiting, so having so much choice is really making me overthink things!

[Da5id Weatherwax]

1 minute ago, nachtai said:

I really do thank everyone for all of the responses! I come from creating for a game that only uses one UV per item/clothing and it has to be box sized so it's limiting, so having so much choice is really making me overthink things!

You can still only use one UV per model - but different materials are different "faces" when uploaded to SL, so can take different texture maps. Their UV layouts can occupy the same face without causing problems. If you were to look at the UV map for that snooker table you'd see the UV layout of the wooden bits overlapping with the one for the cushions and the one for the pockets - everything else is "one face, whole image" - since its either going to be a blank tinted texture or genuinely a single face like the line markings - and on the MODEL's UV map they all overlap - but as separate faces in SL they are textured separately and it works.