I use the brick node to made a brick wall, but cannot see the bricks in preview.So I don't know what size of the bricks until render. How can I see bricks in preview?

:b_uncertain: 

You can't.  IIRC, you can't preview any procedurals.

You could do a bit of calculation to work out the size of your bricks, though.  If you know the size of your wall, you should be able to work out the size of the bricks by dividing the number of 'em by the height and width of the wall you're applying 'em to.

Use the area renderer to see how the bricks render.

You need to have HW Shading on in the Render settings for Preview. This will not work in all cases, but for (simple) bricks this works.

In P9/PP2012 the preview has improved and can show a lot more, but when nodes get too complex, they will not show either. Attached is a screenshot for tiles in PP2012

thanks for the answers.

:b_smile: 

 I learned this from bagginsbill, and it is very useful.

In a scene with NOTHING added, plug your procedure nodes into the Root node of the background. The background is not affected by the camera or the lights. Render to a square  dimension. I like 4096 pixils. Then export the render. I like to do it as TIF file, but any will probably do. You now have a texture that can be applied to an object  by attaching it to the the Diffuse channel of the Root Node, and you can see it in preview.

You may still want to produce your effect with a procedure, but you will be able to make a map of even very complex node set-ups to see how they look in preview, without having to render the whole scene.

With this method you can produce all kinds of maps. The material room is able to do things that are hard to figure out in Photoshop or Gimp.

Thanks BB!  :)

lmk