Using the new H15 workflow , how do you apply materials to primitive groups that are on each agent ie I want to use a different materiel for , legs / arms / head

ie 10 packed agents > the agent has grp_legs , grp_head , group_arms. Ive had a poke around and talk about confusing ! . Its certainly not intuitive !

any ideas >

You do this with the new material stylesheets. It took me a while to get this to work….like you said, not very intuitive, but it works.

This tutorial might get you going. will see if I can do a screen grab once I have a bit of time.

https://vimeo.com/142466794 [vimeo.com]

Thanks I have seen that but its really not that great. Points are skipped over as if they are not important when in reality the Cvex snippets are at the core of doing anything. The shipping examples are coded and dont bother with the H15 “new” workflow.

Rob

Have a look at this file.

I used the default mocap1 dude on a small crowd. He comes standard with groups applied.
You would probably have to re-bake the agent so that Houdini can generate the agent folder with packed geom and walk bclip. Just go to the agent_bake node and hit render to generate them.

If you open a data view and change it to material stylesheets. You will see that I created two overrides on the crowd source. The groups on the mocap1 dude does not live at object level, so you have to create sub targets to dig into the right layer. From here you can override the group and apply a new material. I used skin and blue cloth from my own shopnet1.

Render the agents to see the material overrides.

Let me know if this helps.

Hi, I had a look at your scene file, I can not see any group names being used to override a material ? . See attached for a simple scene of pack prim spheres. The sphere has grp_top and grp bottom. I want to apply the red material to the top group and the blue material to the bottom. overiding the default grey material.



Rob

You have to group copy template's grid points. Then after copy put group transfer to transfer groups from points to packed points (preserve groups in Copy doesn't work?). In material stylesheet set condition type to Point Group.

edit: nevermind, didn't read properly what you want to achieve

Not sure why the file was broken. Sorry about that.

Here is a working version.
You applied the Stylesheet at Scene level (sphere_object1) and just needed to dig one level deeper into Geometry level(the groups) via a Sub Target…that is how I understand it. :?

Just ad a sub target and then apply the override.

With crowds it works the same. You apply the Style to the crowd_source and ad sub-targets to reach the inner hidden groups. You can test to see the hidden groups on a crowd by using a unpack node. This will reveal the group names again, but might slow down your pc if you have tons of agents in the scene.
Let me know if you need more help or if anything is unclear.

PiotrekM, this works without having to transfer groups.

Great stuff, now I can see what exactly is going , I still feel its not exactly user friendly and I am only scratching the surface with the set up ! . I wonder if “style sheets will morph into a general overrides system for all of houdini ”

Thanks

Rob

Hello, it's been some time since you posted but after struggling with crowds for some time I managed to find a workflow that I'm using now. I created a small document to describe it, maybe it can help. I'm just gonna leave it here (I've attached a PDF).

I'm still quite new to Houdini and have further questions in this matter:
How could we create an image plane (render pass) from a group name attribute? I mean the group name we create in “crowdsource” node.

For example, we create a scene with 10 different groups, we name them, and we want to have a mask for every group after we render. We could bind a parameter in the shader? But we have to bind that in every material? For the shoes, hats, bodies, of e.g. 30 different characters? That would be a nightmare.

Another solution: create a simple shader with just the parameter and use it in Takes? But then we render the scene twice - the “normal” render with shaders we created for all the characters and assigned through Material Stylesheets, and then the “masks” render, right? Still not a perfect solution.

There is also this style sheets master class video: https://vimeo.com/155876134 [vimeo.com]

Mark

Yep, but it misses the info I was asking about.

No, sorry, I was not trying to answer your question. I just wanted to add that masterclass link to the original topic of this thread.

Style sheets cannot be used to generate additional image planes, and I don't know that much about rendering outside of style sheets, so I'm not sure how to achieve what you are looking for…

Mark

Hi all,
I undestand but can't get a solution for my problem.
I want to change the material of an agent layer with a style sheet. Inside the setup all prims are packed and no groups are possible for the added layer.

I hope you understand (I have seen all videos;o)

Detlef

SOLVED
OK I answer my own question:

1) before adding the new layer make a group
2) assign a style by point Group and give it the name of the group

But is it possible to use the layer name?

Detlef

Hi Winkel - have you managed to figure this out? I still haven't started to use the agent layers (that's the layer type you're referring to, right?), but the problem will come up eventually

The only help I can give is the stuff I've put in the .pdf file several post above.

I haven't been playing with Houdini from some time but now I'm comming back and also trying to figure out how to do limb detachment. But that's another story
The only info I have is this: www.sidefx.com/docs/houdini/crowds/ragdoll#detaching-limbs-advanced
But I don't have any idea how to use the layers so that the skin doesn't stretch etc.

Hi Loogas,
thanks, I havn' read you pdf but for me it's a bit of trial and error;o)
All the tutorials are made in different Houdini versions, so it's hard to follow the examples.
Now I ran into other problems, but that should be another thread.

Detlef

loogas
Hello, it's been some time since you posted but after struggling with crowds for some time I managed to find a workflow that I'm using now. I created a small document to describe it, maybe it can help. I'm just gonna leave it here (I've attached a PDF).

Thank you so much! This was EXACTLY what i needed.

I find the material sheet/packed prim workflow very convoluted and confusing…to be honest, I still dont understand why people were not happy with the old instancing workflow.What was so bad about that?

Werner Ziemerink
Not sure why the file was broken. Sorry about that.

Here is a working version.
You applied the Stylesheet at Scene level (sphere_object1) and just needed to dig one level deeper into Geometry level(the groups) via a Sub Target…that is how I understand it. :?

Just ad a sub target and then apply the override.

With crowds it works the same. You apply the Style to the crowd_source and ad sub-targets to reach the inner hidden groups. You can test to see the hidden groups on a crowd by using a unpack node. This will reveal the group names again, but might slow down your pc if you have tons of agents in the scene.
Let me know if you need more help or if anything is unclear.

PiotrekM, this works without having to transfer groups.

I know this thread is quite old but I'd like to know where you actually create groups on an agent for the style sheets to choose from. Can't seem to do it.