Hey All,

Ok I can get my VOPS SOP Displacement working namely I believe because I only have to supply the Pos value and not the N normals value. However when I try to pipe the amount variable from veins node into the displacement node value amount and then I pipe dispP into P and dispN into N. I pass the uv vector as a parameter into the pos value for the vein node. I don't have an idea of what the special variable name for the normals is. I tried n, nN, and N with no luck. Can anyone tell me what I am doing wrong or what the magic variable is for the parameter to be passed in from the SOP geometry to the shader node? I would post an image of my network but unfortinately the school has my webspace down again. Which is the primary reason I have not posted on the forms in awhile. Seems like such a simple thing but none the less it has me stumped. Much thanks for any responses.

Cheers,
Nate Nesler

Hey Nate,

I kinda got a little lost in your post, so I just made a quick displacement shader using the veins vop. Hope it can be of use to you and possibly help answer your problems…

dave

http://studentpages.scad.edu/~dquiru20/veindisplace.zip [studentpages.scad.edu]


p.s. if you have trouble figuring out parameter naming conventions, remember you can middle-button click on the input of any vop and select ‘create parameter’.. that will lay down a connected parameter vop with the appropriate names.

I'm not sure I know exactly what the problem is that you are having, but try this,

Global(VOP) N -> Normalize(VOP)

Normalize(VOP) Nn -> Displacement(VOP) Nn

Displacement(VOP) DispP -> Output(VOP) P

Displacement(VOP) DispN -> Output(VOP) N

Shading Layer(VOP) uv -> Veins(VOP) pos

Veins(VOP) ammount -> Displacement(VOP) ammount

That will get you a Vein Displacement shader that sticks to your surface. From there you can hook up whatever other parameters you need to get the effect you want.

Hey Michael,

Didn't Work, but now I am able to post a picture of the network so at least you can see how I did the displacement shader.



I have no clue at this point. The sad thing is that I have gotten displacement shaders to work in houdini. Like I said the SOP Displacement works but unforniately I run out of ram when I try to use it so I have to use a Displacement SHOP.

Cheers,
Nate Nesler

P.S. Thanks for all your help its much apprecitated.

I don't see any obvious problems in your network. Except, you are premultiplying the ammount you get from veins before it goes into the displacement. What you are doing there is effectively the same thing that the scale parameter does in the displacement vop. You can delete that multiply, and pipe veins ammount right into displacement ammount, and pipe your customg Ammount parameter (which is actually Scale) into the scale paramter of the displacement VOP.

Also I told you earlier To take N from globals and normalize it. That's not necesary. I just looked at the VEX code for displament and if nothing is going into the Nn paramter it automagicly assumes normalize(N). So you can delete Global and normalize if you like.

Now, I'm still not exactly sure what your problem is other than you are running out of memory so I made a file that contains a simple version of this same displacement (minus all the extra paramters) both as a SHOP and a SOP.



They both work, but notice that even with nearly 100 times more geometry the SOP version doesn't come anywhere close to the detail in the SHOP version. You should only do SOP displacements if you actually need the geometry for some reason, otherwise if it's just a look you are after, use the SHOP displacement.

Here's the file so you can see the VOP Nets.

http://s91408461.onlinehome.us/displace.hipnc [s91408461.onlinehome.us]

Hey Michael,

Wow there was one thing I found wrong with my shader I did not have uv parameter set to 3 float vector instead I had it set to direct which is a 3 float vector. Caused a problem. However that was not what was keeping it from rendering. There is something wrong in my scene file. None of the displacements are working where at one time they did. I don't know what is wrong. When I copied my displacement into your file and applied it. It worked. However when I applied your displacement into my file it did not work either. Interesting. So there is nothing wrong with the shader at this point. Also I even copied your Shader SOP node to my file and it still did not work. I have no idea why I am not getting displacements on anything even though I previously did and as far as I know I did not make any changes to those previous objects. I am thinking of creating a fresh file and copying my work over from the other file to see if that fixes it. Thank You For All of Your Help I don't think without you posting I would have figured it out nearly as quickly. Frustrating to say the least.

Cheers,
Nate Nesler

The only thing I can think of, is that a SOP displacement needs to be applied to points. If you UV projection is applied to vertecies, it's not going to work.

Hey Michael,

Well I am using the points on the SOP and the SOP was never the problem just the SHOP Version. Its weird that I can get the SOP to apply properly but not the SHOP. I am using UVTexture and not UVProject because my character is animated. Can I use Natural Location or do I need to use something else with a SHOP? Like Vertex or Point. None of my displacements are properly getting applied but I have managed to get some of them to apply. I am applying to Faces.

Cheers,
Nate Nesler