DjangoBB LoFi version

Root » Houdini Indie and Apprentice » Random textures from pool

firefly9000

April 24, 2018 12:34:18

What I'd like to do is the following:

I have about 4k groups that come as part of 1 obj.

I would like to assign shaders in the materials as such:

/matnet1/shader_**for each group pick a random nr from 1 to 5**

or, alternatively in the shader itself in the texture field if possible. Whatever is deemed simpler.

I'm sure I must be missing something as all the answers I found online were old and required adding of attributes and really complicated workflows some with sops that no longer exist.

Can someone point me in the right direction?

Thank you

huey_yeng

April 24, 2018 14:57:50

You can use Python to bulk apply the shaders in a random shuffle manner for the 4000(!) groups.

I'm still not familiar with the Python commands for assigning shaders but you can do something like this.

import random

shaders = [shader1, shader2, shader3, shader4, shader5]  # The shaders should go here

random.shuffle(shaders)
for each in shaders:
    # the code to apply the shaders goes here

firefly9000

April 24, 2018 15:54:19

huey_yeng
Member
59 posts
Joined: Nov. 2016
Offline

today 2:57 p.m.
You can use Python to bulk apply the shaders in a random shuffle manner for the 4000(!) groups.

I'm still not familiar with the Python commands for assigning shaders but you can do something like this.

Thank you for trying to help. I had figured out the randomization bit (though I did it differently), but I got stuck at the same part you did: Assigning the shaders programmatically per group.

My idea was to call them up on a per group basis (in the Material sop) but I have no clue how to do it… or even if it's doable or the right strategy.

tamte

April 24, 2018 17:44:22

if your groups are non-overlapping use Name SOP to convert them to name attribute (Name From Group checkbox, Group Mask: *)
then use random_shash() VEX to generate your 1-5 number from the name attrib and build the texture path override or shader path based on that

like this for example (Prim Wrangle, s@name is unique prim per-group name generated from groups):

int matid = floor(random_shash(s@name)%5)+1;
//set material
s@shop_materialpath = sprintf("/math/principledshader%d", matid );

// OR override basecolor_texture 
s@basecolor_texture = sprintf("/path/to/texture%d.rat", matid);