2d displacing and Max units. Possible bug?

[windowlicker]

Yesterday I tried to get some proper renderings out of a 2d displaced wall, but it was completely impossible. Seemed to... just not work! I gave up and solved it in another way, but today I made some tests.

Two identical scenes are created - one with the max units set 1 unit = 1 mm, and the other one set 1 unit = 100 mm. Identical scene environments are used (vray plane as ground, vray phys cam, vray sun, hdri env).
In the scene a sphere with a radius of 500mm is created. Real world map size and generate mapping cooridantes on. On that sphere, a vray displacement mod set to "2d mapping" with an amount of 20mm, and a resolution of 512 and precision 8.
On the sphere a simple gray vray material is used. A checker texture, with the dimensions of 100mm x 100mm is used for displacing.

In the 1:100 scene everything works alright. In the 1:1 scene... it does something. But it is not at all the correct result. Check the attachments and see.

Is this a known bug? Tried searching for it, but came up pretty much blank.

[vlado]

It is odd indeed. Can you attach the scene here or send it to me at vlado@chaosgroup.com?

Best regards,
Vlado

[windowlicker]

Sent the file per email. Eagerly awaiting your solution.

[windowlicker]

There seems to be some kind of error with 2d displacement when using real world map size. Maps look alright in the viewport, but renders completely different. When using the same maps/materials but using 3d displacement, everything works perfectly. Changing to "normal" UVW-mapping seems to solve the problem.

Anyone else has any experience from this?

[vlado]

It is because 2d displacement does not work with the "Tiling" parameters of Bitmap textures, and the "Real world map size" uses these parameters. It is unfortunately not easy to fix. On the other hand, 3d displacement works fine.

Best regards,
Vlado

[windowlicker]

Well, that must the problem, then. Just don't use Real world map size when 2d displacing. Might want to add a note about that to this page though: http://www.spot3d.com/vray/help/150S...Mod_params.htm

To bad it's not an easy fix, because it would be very useful - at our studio we're working almost exclusively with Real world size maps.

(It's still a bit weird that it seems to work some times.... and sometimes not at all.)

[vlado]

Yep, will add a note for this.

Best regards,
Vlado

[tricky]

Yep, will add a note for this.

Best regards,
Vlado

Any solution to this yet? We use BerconTile to generate our bricks etc, so we need to be able to use Real World Mapping.