Textures on Big Structures

I have a question as to what is the best way to handle a large structure like a skyscraper's texture.

The structure is 20 meters wide and 30 meters tall using 6 10m X 10m prims. I have a texture that I've sized to 1024x512.

Is it better to:
1. Cut the image up to 6 512x512 textures and post one on each prim?

Or

2. Use the whole texture on each prim and adjust the size and offset of the position.

My question is based on if you use the same texture on multiple prims, only one texture download is done for all prims as opposed to (in this case) 6 separate texture downloads.

I want to make sure I can cut down on lag and expedite the loading of the textures.

Thanks!

From a caching and memory use standpoint, a single texture used multiple times costs less than multiple textures used once. However, splitting up the texture might make it look better when textured over a very large area, depending on the texture and the overall desired look of the object.

I have recently covered a 20x20 area (4 prims) with one texture using repeat = 0.5 and applying the right offsets for each part. It cost me L$ 30 less in uploads and three textures less to keep track of in my inventory. I like the result.

Dividing up in (2x) three parts may give you some numerical rounding problems at the places where the prims meet, because 1/3 cannot be accurately represented as a floating point number. Depending on you texture and your luck that may or may not be visible.

what file-formats are allowed to use?
maybe u can use vector graphics like these?

Your second option is the way to go. You are correct that one download is more efficient than six separate ones. Don't cut up your texture.

As White said, splitting over 3 parts won't be mathematically perfect, but it will be close enough that you won't notice. If you want to ensure there's not a single lost pixel though, you could pad your texture on a larger canvas. That might be the best thing to do anyway since your 3:2 height to width ratio doesn't fit neatly into power-of-two sizing.

Here's what I'd probably do. Start with a texture size that is right for the proportions of your build, say, 256x768. Then mount that texture on a 256x1024 canvas. When you apply the texture to you build, the repeats will end up needing to be .5 on the horizontal, and .25 on the vertical. Offset accordingly to show the entire image.

You're wasting 1/4 of the canvas as empty space this way, but you could recover that by using that quarter for another texture to go elsewhere in the build, and then nothing will have been lost. That's what I'd do if it were me.


Abraham, the file formats that SL can use are listed in the sticky at the top of this forum, entitled "Texture Size, Pixel Counts, Video Memory, and File Formats". I'd highly recommend you read it.

So you know, those PSD's on Robin's website are stictly for use on your own computer when making clothing. SL cannot use them directly.

Also, just for clarity, they're not actually vector formats. They do contain what Photoshop calls "vector smart objects", but they're still raster images. While vector smart objects do use some vector math, which is where they get their name, they're applying that math to a raster source object to spit out a scaled raster target object. It's Photoshop's way of making the resizing process a bit more lossless than it otherwise would be. It's not producing an actual vector image file.

Even if it were though, I don't see how that would be of any particular benefit for spreading a texture over multiple prims. Care to explain your reasoning for why it would?

ill try it and tell u when its done.

What is it you're planning to try? SL cannot use vector images. So, how is it that you believe vectors will help with Rex's question? I'd really like to know what you have in mind.

I generally resize my textures by power of 2s I've found in the long run the textures always look better, even when it's slightly distorted it and I re-stretch it out and it still looks good. Great idea about the empty space. I'll remember that trick.

I have no problems either with the cutting or stretching to fit, again cause I stick to powers of 2 I think

I didn't know if SL actually did a single download of a texture found on multiple prims or if I was about to have 6 downloads of the same 1024x512 texture. I tried several test of both but the results were inconclusive as I have a fast machine with a mega video card.