Houdini 11 and Ptex

[Orange35]

Hi, guys! For a long time looking at the forum, so there was reason to write the question and ask the masters of the package - what am I doing wrong? How to tighten ptex texture on the model correctly?

Sources took from here: http://ptex.us/samples.html

[Orange35]

Windows 7 x64, by the way

[dbukovec]

hi!

You have used a material which I think is not supporting ptex, dive inside vop network and drop down a ptex texture note connect it to surface model and try to render it.

[calix]

I also have problems with the ptex sample files. The textures don't get assigned correctly...

[Marc]

Hey

I just tested the same scene here on ubuntu and it works fine. I don't get any warnings/errors/etc. Perhaps it's a windows only problem?

M

[calix]

Here's another one...I'm on OSX. Did you use any other nodes besides the PTexture node?

[Orange35]

Thanks for answers!

Hey

I just tested the same scene here on ubuntu and it works fine. I don't get any warnings/errors/etc. Perhaps it's a windows only problem?

M

Yes, probably.. tried this scene on the second computer with better performance, on same windows 7 - render goes to the middle, but still breaks by console with an errors.

[Marc]

oddly enough, I got those warnings later but my renders never stopped... I'm not sure why yours are crashing. @calix, I used the mantra surface material and I built my own and they both worked. I'll upload my file tomorrow. Your teapot doesn't look right .

M

[calix]

Thanks Marc! ;-)

[Marc]

Hey Calix

Your bunny is correct, your teapot just needs a reverse SOP... Here's an attached hipfile anyway to show what I mean...

Cheers

M

teapot.hip

[calix]

Thanks for the tip Marc! Texture is good now, but it renders only into the red channel with your shader...see the image. When I use the PTexture node in a Material Shader Builder it renders correctly.

teapot_good.hip

[Marc]

yeah it's weird, it was rendering fine for me at first and then I changed something and it just rendered into the red channel. I didn't have time to troubleshoot it . Besides, red teapots are cool...

[calix]

maybe the ptex support in shaders without the ptexture node is buggy???

[Orange35]

maybe the ptex support in shaders without the ptexture node is buggy???

Yes, apparently so

[crunch]

I also have problems with the ptex sample files. The textures don't get assigned correctly...

The bunny is intended to be rendered as a Loop subdivision surface. Mantra doesn't support this type of subdivision surface. If you render as polygons, prman doesn't render the texture correctly either.

It does seem that the polygons of a .obj file import need to be reversed to render correctly though.

I've attached an updated version of the teapot example from the ptex web site. Hope this helps (there's a .hip file in there).

h_teapot.zip

[haikalle]

Thanks for the hip file. Have to check if this the key how I can make my 3d-coat Ptex textures to work in houdini.

Edited September 10, 2010 by haikalle

[haikalle]

I found the reason why 3d-coat PTex dosen't work in houdini. It´s because .obj format. Right now 3d-coat writes it as:

f v1/vt1/vn1 v2/vt2/vn2 v3/vt3/vn3 ... (which is correct way but houdini has some problems to understand it when used with Ptex)

if I change it into this:

f v1//vn1 v2//vn2 v3//vn3 ... (samples from ptex.us use this way)

It works and I get beatiful Ptextures. It seams that it's more houdini issue than 3d-coat. Hope we can find a solution.

It's not so hard to write a script to change the .obj file but it should not have this kind of issue in the first place. Thanks.

[edward]

Can't you just load the .obj file and delete the texture attribute?

[haikalle]

Can't you just load the .obj file and delete the texture attribute?

How you do that in houdini?. That would be easy fix. But it's good to know this limitation.

[edward]

Attribute SOP.