Best image file for textures in metal ray

[MMallmann]

Hi,

I wondering if there is something like a best image format for textures in conjunction with mental ray. I mean there might be a format that mental ray might process better than other ones in terms of speed, memory usage and stabilty.

Can anyone help me out here?

Cheers
Max

P.S. I do not mean map files. More like png ,etc

[dbukovec]

Since maya converts every image format to IFF internally, and according to docs IFF can be memory mapped, thats the best format for render. But if anyone has a better idea please share.
Also its vital that You set the filter type to MipMap, and filter size to 0.3 (at the Effects tab of the file node). This way U get sharp textures, by default (quadratic and filter 1.0) mr renders textures very blurry.
Also use Triangle filtering from 1.6 to 2.0. Triangle filtering tends to a bit faster than mitchel, and 1.6 gives u sharp filtering also.

cheers
danel

[InTercepto]

Well I use TGA format all the time because it is simple and everyone reads it. But when it comes to speed it would be nice to convert some textures to the internal mentalray MAP format so that MR doesnt need to convert it when rendering. Once the picture is in MAP (pyramidal one) it can flush the textures easily and save a lot of ram...

[hkspowers]

As was stated earlier it is best to render your frames as iff. I usually convert all of my images to tiff or tga. I like tga because it is very universal and supports 5 channels I believe tiff is restricted to 4 channels. As for my texture files I like to save as sgi it is lossless and it is very small. I have noticed in my renders sgi is consistently around half the size as my tiff.

[yashu]

use mentalray's map format, it's the most efficient of all these since it's memory mapped texture and it does not get converted to maya iff (i think only if you use it with the mentalrayTexture node).

[THX1138]

As was stated earlier it is best to render your frames as iff. I usually convert all of my images to tiff or tga. I like tga because it is very universal and supports 5 channels I believe tiff is restricted to 4 channels. As for my texture files I like to save as sgi it is lossless and it is very small. I have noticed in my renders sgi is consistently around half the size as my tiff.

I preffer .tga's as my choice of file format. As you said they are more universal and support 5 channels. Reguarding .sgi's, I never knew it was a common format. Do Adobe products support it?

[jj80]

Map files are equivalent to bot files, in that they are disk cached. memory mapable, textures. This has advantages and disadvantages:
One one hand, mental ray can decide how much to load into memory, which keeps memory usage low (i.e. if an object is far away from the camera). On the other hand, it takes longer to read and write them, just because they're being read from disc instead of from memory. Especially if you're loading them over the network, this can turn into a big dissadvantage (see the 'nfs' part in the docs).

Otherwise, the usual maya rules apply, keep them square, to the power of 8 (1024, 2048 etc) and in maya's internal format, iff.
Avoid tiffs, they can be very nasty.

Ah yeh, if you don't convert to iff's first, maya will do it for you, which can take ages. And one more tip: Mental Ray bails if you have missing textures, so keep your scenes clean :cool:

Iff is able to handle up to 32bit of color depth if I am not mistaken.
And finally, a great format to render to is openEXR.

Ah yeh, and finally finally, here the link to the manual ;)
file:///C:/Program%20Files/Alias/Maya8.0/docs/Maya8.0/en_US/wwhelp/wwhimpl/js/html/wwhelp.htm

[THX1138]

Errr, might want to fix that link. Doesn't seem to work.

[bmcaff]

Reguarding .sgi's, I never knew it was a common format. Do Adobe products support it?

Yes, SGI (or RGB) files are supported by photoshop and in fact i personally find the saving and reading of SGIs much more reliable than IFF. I always save my textures in SGI format and convert to MAP with a drag and drop desktop BAT file for ease of use. I can't say I have a real good reason for using them but more of a hangover from using Alias so long. Even if Maya converts them internally I don't notice the time hit so much and it certainly saves me time over saving an IFF from photoshop.

On Output formats, I usually use IFF but i find that about about 5000 pixels photoshop will not open them. I often have to comvert them to TGAs or, if I think about it before hand I'll render them to TGA. I am starting to use openEXR a lot more these days.

[hkspowers]

I went to highend3d and got the Photoshop plug-in to read and write sgi format. I do not think Photoshop reads it natively.

[bmcaff]

Yes, quite right.. the plugin needs to be installed and Highend3d is where to get it alright.
I had the feeling that I got it on the Photoshop CD at some time in the past few upgrades but it's just one of those things that I do without too much thinking.

[jj80]

THX, I'm not sure what's wrong with that link, but you can right click on it, copy it and paste it in ur adress bar and it'll work as long as you have maya 8 installed in the default location on windows. Otherwise just search ur docs for "mental ray file textures"...

[THX1138]

it'll work as long as you have maya 8 installed

Well That explains it as I only have maya 6.5 . I also checked my docs and I did not have a mentalray file textures section that I noticed...bummer.