I am having a difficult time with SHOP and VEX. I am not sure that I at all like the texturing tools. Either they are too simplistic, or their power is burried too deeply for a new user. Or I am too used to Maya and 3DS MAX way of doing things. Some basic things I am uable to figire out and they are not covered in eith Help PDF or Tutorial PDF. So I am asking for some help.
1. Why does neither VEX Supermaterial or VEX Texture operator NOT identify houdini PIC sequences as sequences? Only as individual files. Those same files ARE identified as sequences in COPs and when used as backround images. I tried placing $F after name so the format is name$F.pic. But still only 1st frame of sequence is used. How do I get to use file sequence as texture.
2. Supermaterial does not act very super. While it has many fields, they are limited to single file. How would, say, 5 color maps be mixed in diffuse color channell. Or is that done only in VEX?
3. How come VEX standard materials have no texture fields? Aside from Supermaterial. Is it becouse that VEX Standard materials are just simple examples and that real shaders for Mantra are created in VEX?
4. I am unable to use any built in shadow shaders. Adding any shadow shader to light, breaks Mantra. Basically Mantra does not launch.
5. I swear that I saw Hoiudini users doing rendered previews of shaders in VEX. Even using select regions, like in XSI and Maya. Where is that? Yet I am only able to see the OpenGL versions. Setting SHOP or VEX to high resolution display does not change this.
I am sure all this problems are due to my inexperience. But the major questions is. Is throrough knowledge of VEX , i.e. programming is required to create production materials. In Maya and MAX, I create decent materials with built in tools. I am afraid to admit my own mental limits, but I am unabke to comprehend the VEX Help tutorial.
David Rindner
Hi David
1) About the VEX Texture, are you talking about the VOP or SHOP?
As far as loading the texture sequence goes, are you loading it from disk or from COP itself?
Make sure that you load your sequence into your supermat's Diffusion channel (diffmap), and not Ambient channel. So I have something like $JOB/test/bar.$F.pic in the diffmap field of the supermat shader. That seems to work fine for me – both padded and unpadded.
Before you apply this supermat to your geometry, please make sure that you have a UV TExture SOP applied before you append a Shader SOp afterward. This will create UV coordinate to the geometry for the texture to work. Now, you probably wondered how come you don't see any texture in your viewport. This is because the OpenGL's Texture Map didn't have any shader information. The OpenGL tab of your shader are solely for previewing purposes. So, in your supermat's OpenGL tab, just make sure that your Texture Map field is referenced (or just copy and paste) from your diffmap field of your shader tab.
2) Actually, I do think that Super Material is… well, quite super to a point that it can be a bit inefficient – but that's in the sense that this shader packed wich LOTS of abilities to manipulate many various color channels and properties. If you want to have 5 color maps mixed in the, say, diffuse channel – you should probably do the mixing in COP and reference that COP to your shader. Or of course, there's always that Layered Surface SHOP.
If you want to be able to reference a COP in your shader, you can just use the op: command in your, say, diffmap field. (i.e. op
img/cop_net/my_COP). Thus, you won't need to render all your COP stuff out. However, using this method does have a bit of trade off because at render time, you COP would have to cook first before it can pass its information out to your shader.
3) There are quite a couple of the VEX shaders in SHOP are actually coming from RenderMan's basic shaders. For (a very popular) example, Plastic SHOP. They can accept textures, just isn't built in… In other word, we can re-assemble them to make them to some of the most crazy and insane shaders from VOP/VEX.
4) Hmm…. I am not sure… I'll have to leave this up to SideFX personnel.
5) Hmm… Do you mean that the shader/textures are applied to the geometry and we can see them in a regular viewport instead of just shader preview window? I think that #1 should covers this.
ANyhow… I hope that helped…
1) About the VEX Texture, are you talking about the VOP or SHOP?
As far as loading the texture sequence goes, are you loading it from disk or from COP itself?
Make sure that you load your sequence into your supermat's Diffusion channel (diffmap), and not Ambient channel. So I have something like $JOB/test/bar.$F.pic in the diffmap field of the supermat shader. That seems to work fine for me – both padded and unpadded.
Before you apply this supermat to your geometry, please make sure that you have a UV TExture SOP applied before you append a Shader SOp afterward. This will create UV coordinate to the geometry for the texture to work. Now, you probably wondered how come you don't see any texture in your viewport. This is because the OpenGL's Texture Map didn't have any shader information. The OpenGL tab of your shader are solely for previewing purposes. So, in your supermat's OpenGL tab, just make sure that your Texture Map field is referenced (or just copy and paste) from your diffmap field of your shader tab.
2) Actually, I do think that Super Material is… well, quite super to a point that it can be a bit inefficient – but that's in the sense that this shader packed wich LOTS of abilities to manipulate many various color channels and properties. If you want to have 5 color maps mixed in the, say, diffuse channel – you should probably do the mixing in COP and reference that COP to your shader. Or of course, there's always that Layered Surface SHOP.
If you want to be able to reference a COP in your shader, you can just use the op: command in your, say, diffmap field. (i.e. opimg/cop_net/my_COP). Thus, you won't need to render all your COP stuff out. However, using this method does have a bit of trade off because at render time, you COP would have to cook first before it can pass its information out to your shader.3) There are quite a couple of the VEX shaders in SHOP are actually coming from RenderMan's basic shaders. For (a very popular) example, Plastic SHOP. They can accept textures, just isn't built in… In other word, we can re-assemble them to make them to some of the most crazy and insane shaders from VOP/VEX.
4) Hmm…. I am not sure… I'll have to leave this up to SideFX personnel.
5) Hmm… Do you mean that the shader/textures are applied to the geometry and we can see them in a regular viewport instead of just shader preview window? I think that #1 should covers this.
ANyhow… I hope that helped…
5. In the Object or SOP (Geometry) Viewer, hit Tab, type Render, hit enter. Now box select the region you wish to render.
On edward's point, remember to turn Secure Selection ON. A bug seems to prevent it from working if SS is OFF.
Thank everyone.
Aha! Render SOP does not appear in Network viewer only when pointer is over a scene viewer. Explaines why I never saw it. So is it a SOP or something else. If you call up TAB and R key over network viewer Render does not appear as an option. Still that was VERY VALUABLE info thank you. One note. This option seems, on my Windows, bit prone to crashing. Especcialy if view is orbited/panned/zoomed while Render preview box is on screen.
One question that has not been answred is exactly how do I feed COP into VEX and SHOP?
Its very strange how my competence in Houdini is distributed. With SOPs, I could teach a gradiuate level course in modeling and character rigging. With IK I am fairly priofficient. With COPs, I am allright, I can get by. But I am a total neophyte when it comes to shading and lighting in Houdini. Technically it seems to me the most complex and is kicking my but. Maya's Hypershade and lighting is simple by comparrisson.
Dave Rindner
PS. I am finding that magnets with elonagated metaballs make a somewhat effective musculature substitute for facial rigging.
Metaballs arrays on spline coupled with Magnet approximate well the muscle based deformers that Secret Lab (RIP) developed, just not as sophisticated or elegant as SL stuff in Maya.
Aha! Render SOP does not appear in Network viewer only when pointer is over a scene viewer. Explaines why I never saw it. So is it a SOP or something else. If you call up TAB and R key over network viewer Render does not appear as an option. Still that was VERY VALUABLE info thank you. One note. This option seems, on my Windows, bit prone to crashing. Especcialy if view is orbited/panned/zoomed while Render preview box is on screen.
One question that has not been answred is exactly how do I feed COP into VEX and SHOP?
Its very strange how my competence in Houdini is distributed. With SOPs, I could teach a gradiuate level course in modeling and character rigging. With IK I am fairly priofficient. With COPs, I am allright, I can get by. But I am a total neophyte when it comes to shading and lighting in Houdini. Technically it seems to me the most complex and is kicking my but. Maya's Hypershade and lighting is simple by comparrisson.
Dave Rindner
PS. I am finding that magnets with elonagated metaballs make a somewhat effective musculature substitute for facial rigging.
Metaballs arrays on spline coupled with Magnet approximate well the muscle based deformers that Secret Lab (RIP) developed, just not as sophisticated or elegant as SL stuff in Maya.
The Viewer's tab menu has a set of tools under “Generic” which are all the tools that are viewer specific. Also note that all the higher-level character tools are found in the Object Viewer's tab menu, and not in the network editor's.