Textures Size

[FamilyGuy]

Hi. I'm trying to understand the problem of texture size in Octan. I have a scene where a model is 141MB and texture 366MB:
- texture 1 (jpg_6000x8000, file size 7,49MB)
- texture 2 (jpg_6000x8000, file size 7,49MB)
- texture 3 (jpg_6000x8000, file size 11,2MB)
- texture 4 (jpg_6000x8000, file size 11,2MB)
totality=37,38MB

So why Octan takes 366MB?
How to work with textures - is there a topic devoted to this issue?

[matej]

jpg is compressed. The amount of megabytes on disk is not equal the actual amount that the image takes when loaded into ram. RGB = 3 bytes / pixel

[FamilyGuy]

Thanks Matej! You really helped me to calculate the scene. I scaled textures to 1200x800 and they take only 12MB without loss of quality.

[necko77]

nice tip...thx

[matej]

Guys when you are calculating megabytes, remember that 1 Mb = 1024 kb = 1024^2 b
So the formula would be:

(width x height x 3) / (1024^2) = number of Mb in memory

So your textures take "less"; ~11 Mb

If the image has alpha channel, that's another byte / pixel

[gzavye]

silly question (1024^2) is (1024*1024)?
btw, Octane prefer texture with power of 2 size or it can deal (optimise) with other size?

[matej]

silly question (1024^2) is (1024*1024)?

Yes

btw, Octane prefer texture with power of 2 size or it can deal (optimise) with other size?

Good question. Hopefully someone form the dev team will answer that.

[FamilyGuy]

"btw, Octane prefer texture with power of 2 size or it can deal (optimise) with other size?

What do you mean by that. Can you give an example?

[gzavye]

Historically, video cards prefer pwr of 2 size for textures : 512*512, 1024*1024, 256*512...
I know that modern softwares are able to dynamically resize nSize texture, but in this case rendering may be less efficient.
So what type Octane prefers?

[irene]

Does anybody know the answer to this? What texture size/side relation is best in Octane? Power of 2 square (i.e. 512*512 etc...) ? Or does it not matter?