How to determine proper bitmap size/resolution for a scene?

[Greyfish]

I've been pulling whats left of my hair out trying to determine why my ground/gravel/concrete materials comes out grainy an distorted. I've found some high res. bitmaps and am using them but I think I'm missing a key detail.

 

I've read that the size of the bitmap has to be in correlation to the resolution of the final

render but I couldn't find the equation for it.

 

Somewhere else I've read stated you should "stitch" them together in Pshop then apply them.

 

I'm modeling a simple back yard, it can't be that hard to make gravel or stained concrete

look good with high res images, so it must be something I'm missing. I've seen street blocks in here look better then the backyard patio I'm rendering! Lol...

 

Help in this would be greatly appreciated from all those in the know.

Edited April 24, 2012 by Greyfish

[dmv79]

Post an image of what you're getting so we can help. As a general rule, if you're rendering a 2000X2000 pixel image, you shouldn't need any texture larger than that. And this would only be the case if the texture is not tiled and the object covers a large portion of the image. Too many large textures in your scene will send memory usage through the roof.

[ironwind]

In general I would say that the minimun bitmap size should be 1,5 X size on screen.

So if your a yard is 1000 pixels wide when rendered on screen then the texture size should be 1500 pixels wide.

If you are using Mental ray as a render engine try to lower the "blur" option on the bitmap from default 1.0 to say 0.5 or lower as it migt sharpen the texture a bit (if u get artifacts try to increase instead).

And don't forget about uwv-mapping... or nothing will ever work.