Textures, primer for uploading?

I there anywhere that has a guide to getting textures into SL?

For instance, if I scan in a picture of a stained glass window I want to use an SL texture, does it need to have an alpha channel?

I read somewhere that 32 bit targa file is the optimal format....

It would be really good to have this information in a sticky at the top of this forum....

short answer is you only need an alpha channel if you want part of the texture transparent and part not. if you want the whole thing to have the same transparency or no transparency you shouldn't use textures with an alpha channel. they take up more memory so if you don't need them it's a useless drain on people.

TGA is good to use but you can also use BMP or JPEG (no alpha channels). they all get converted to the same thing when you upload them so it depends on your preference and how much hard drive space you want to use to store the textures you made before you upload them.

also try to use the smallest possible texture that still gets the job done. 256x256 with a lil bit of sharpening often looks just as good as 512x512 and takes up 1/4 the memory. also look at how big your object is going to be. smaller objects can get away with smaller textures and it speeds things up for everybody. the Lindens have said alot of textures cause more lag than alot of prims so if you can limit the number you use that's good. try not to go over 512x512 for anything and your neighbors will like you better.

Thank you!!!!

I'm not positive, but I believe everything gets converted to JPEG 2000, an optionally lossless compression. That would make BMP, & TGA files more desireable since you don't have to worry about image degradation due to lossy compression from standard JPEG files. Maybe someone can confirm this.

Confirmed.


On a related note, you should NEVER use jpeg's for graphic arts anyway. The quality is terrible, and gets worse each and every time the file is opened and closed. Jpeg's are only good for what they are meant for, which is web pages. Their small size makes them ideal for the web, where transmission speed is infinitely more important than image quality, but they are not at all suited for 3D graphics applications or for print, where quality is the most important thing.

Generally speaking, if you are creating a high quality image for the screen, save it as TGA. If it's for print, save it as TIFF. Never use a compressed format unless it's for the web.

JPG at highest quality is mostly lossless and you won't notice any artifacting unless you really hunt for it. I usually save stuff as TGA with RLE compression. Either is fine. You wouldn't want to save as highest quality JPG for something that's going to print but for SL it's prefectly fine.

That's true if all you're doing is a single save. However, if you have an image saved as jpeg that needs to be altered (either because it's unfinished, or you want to add a little bit to it, or you want to change the color scheme, whatever), you're gonna need to open it (decompress), change it, and resave it (re-compress). Every time you do that, it will automatically lose quality. You'll be suprised how soon it starts to look like garbage. If you don't care about that sort of thing, then go for it, but my point is why bother with jpeg at all when you can easily use a lossless format that will last forever?

You never know when you might want to use an old texture for a new purpose, and that very often requires some re-work, which as I said means quality loss with jpeg's. It's that whole copy of a copy of a copy thing.

If you're concerned about hard drive space, spend a few dollars and get yourself a pack of 100 CDR's. A 512x512 TGA is exactly 1MB. Every CD will hold 700 of them. One hundred CD's means 70,000 images. Is that not enough?

Chip, usually you and I agree on things, but it seems that on the occasions when we disagree, we really disagree.

Good point Chosen I've never been known for my ability to plan ahead, hehe