Texture appears to increase complexity of mesh garment

[Semirans]

Hello. I have a question about mesh complexity in SL
I don't make mesh, so I buy the blanks and then make textures for them.  Recently I noticed that applying my texture to the blank caused the complexity to jump 19k (from 6k to 25k)
I downloaded the texture that the creator gave with the blank and compared size, pixel density, color type and bits
Both textures are 1024, identical in dimensions, both RGB and 8bit at 72pixels per inch.  They are almost identical in sizes (840k vs 1080k) I am at a loss as to why my texture is increasing the complexity while the creator texture does not.  I don't know what else to look at to figure out how complexity is measured.  Thank you in advance.

[ChinRey]

2 hours ago, Semirans said:

I don't know what else to look at to figure out how complexity is measured.

Here it is:

http://wiki.secondlife.com/wiki/Mesh/Rendering_weight

The most likely explanation is that your texture has a rogue alpha channel. Gimp, Photoshop and Paint.net all tend to add ab alpha channel by default and it's important to remember to remove it before you upload (unless you actually need it of course). How you do that depends on what software you use so we need to know that before we can give you detailed isntructions.

Edited September 1, 2019 by ChinRey

[Semirans]

I uploaded the texture as a jpg instead of my normal png file and I do not have the issue with that texture.  I am using PS. Is the rogue alpha channel you are talking about any transparent parts i might want to have on the garment? I am going to read your link.  I very much appreciate your reply.

[Kyrah Abattoir]

You're shooting yourself in the foot saving files as jpeg due to the lossy compression the jpeg format uses. All uploaded textures are re-compressed as Jpeg2000, so your texture is effectively degraded twice.

Size on disk doesn't matter, all that matters is the total pixel count and whether those pixels are 24bit (RGB) or 32 bit (RGB + Alpha).

Depending of the tools you use, png files might sneak in an alpha channel which causes the texture to bump to 32 bit.

[Cackle Amore]

Honestly, I see no problem with using jpg, most programs these days save them pretty well these days, gimp even has a slider for the quality of it's compression to still keep it lookin good.

Plus, even if you did find a way to scrub any hidden alpha a program might of added, SL seems to add it back itself from what I've seen.

[Kyrah Abattoir]

1 hour ago, Digit Gears said:

Honestly, I see no problem with using jpg, most programs these days save them pretty well these days, gimp even has a slider for the quality of it's compression to still keep it lookin good.

Plus, even if you did find a way to scrub any hidden alpha a program might of added, SL seems to add it back itself from what I've seen.

I just use tga for everything, never had any problem.

[ChinRey]

10 hours ago, Semirans said:

I uploaded the texture as a jpg instead of my normal png file and I do not have the issue with that texture.

That's a quick-and-dirty way to fix a rogue alpha since the jpg format doesn't have an alpha channel. If the quality loss from the jpeg compression is acceptable, the problem should be solved.

 

10 hours ago, Semirans said:

Is the rogue alpha channel you are talking about any transparent parts i might want to have on the garment?

That is correct. The alpha channel is where the transparency values for each pixel of the texture is stored and it adds a bit to the file size and a lot to the render weight. A rogue alpha is an alpha channel for a texture that doesn't actually use transparency at all. It's a waste of resources and can also sometimes cause alpha sorting problems in-world.

[Love Zhaoying]

1 hour ago, ChinRey said:

rogue alpha

https://starwars.fandom.com/wiki/Rogue_Alpha

[Semirans]

Thank you so much for the replies.  Clothing making is much more complicated than I ever anticipated and everytime I make something, some issue arises that I didnt even know to ask about.  But I love making things for my avatar. good cigar.