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Technical Discussion » emission color not working - emitcolorr, emitcolorb, emitcolorg
- jsmack
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Works for me. Did you make a 3 element float attribute called “emitcolor”? This is the default type if you bind to a vector, or use an attribute expression sop set to custom vector.
Technical Discussion » CHOP Constraints with continuous sampling
- jsmack
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Is it possible to allow continuous sampling of constraint CHOPs? As in, always cook at current time sample, the way a vop using @Time/@Frame, would? I found CHOP constraints are not usable for animation with motion blur, (without changing the sample rate to something like 9600, or some other value approaching continuous), because the sample rate is discrete. Switching from single sample to a frame range allows for interpolation between samples at least, but is much less interactive as the entire sequence must be cached after any change. The old object constraints seemed to operate on cook, allowing for non-discrete sampling.
Technical Discussion » set the Operator style to VEX type, and set the Network Type to Geometry Operator not possible
- jsmack
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Oh snap, is the SOP VEX context all but deprecated? You will probably need to create them directly from vfl source now.
vcc --vfl-input mysopnode.vfl --hda-output mysopnode.hda
Edited by jsmack - March 20, 2017 11:20:24
Technical Discussion » Unable to get group sop
- jsmack
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Technical Discussion » Back lit single sided geo SSS with principled shader
- jsmack
- 7770 posts
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You can, but it's broken, you can make it work with:
then add the render property:
vm_smoothP “Fix Shadow Terminator”
and disable it.
vector diff_color,trans_color; bsdf f; vector nn,ni,tng; diff_color = set(0.1,0.35,0.001); trans_color = set(0.05,0.15,0.0001); nn = normalize(N); ni = normalize(I); nn = frontface(nn,ni); tng = select(dot(nn,Ng),Ng,-Ng); f = 2.0 * ( diff_color * diffuse(nn,tng,"label","diffuse") + trans_color * translucent(-nn,-tng,"label","refract") );
then add the render property:
vm_smoothP “Fix Shadow Terminator”
and disable it.
Houdini Indie and Apprentice » Noise on uniform volume shader
- jsmack
- 7770 posts
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Are talking about the displacement noise settings? AFAIK, you can't vary density of a uniform volume, because it is as it says on the tin, “Uniform.”
Technical Discussion » Unable to load HFS OpenCl platform
- jsmack
- 7770 posts
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I get that message, but it works (using my gpu) anyways. Are you certain that it is not working?
(I'm on windows)
(I'm on windows)
Houdini Lounge » Render deep without saving beauty
- jsmack
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Houdini Indie and Apprentice » Assigning colors to VDB meshes
- jsmack
- 7770 posts
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Materials have no effect on alembic export. it will simply add an unusable property. Simply add the color attribute ‘Cd’, either point or vertex. When importing into maya, add -rcs to the AbcImport mel command to import the color set data.
https://www.sidefx.com/forum/topic/38939/ [sidefx.com]
Edit:
according to the last post in that thread, you don't even need -rcs if you are using a modern version of houdini to export.
https://www.sidefx.com/forum/topic/38939/ [sidefx.com]
Edit:
according to the last post in that thread, you don't even need -rcs if you are using a modern version of houdini to export.
Edited by jsmack - March 15, 2017 00:21:48
Houdini Indie and Apprentice » Checking data types in VOPS?
- jsmack
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bonsak
They are color coded.
- Green is vector.
- Light blue is float.
- Blue is integer.
- Beige is file/geo.
- Purple is matrix.
-b
Lol, what about all the structs tho?
Houdini Lounge » Mantra surface deprecated?
- jsmack
- 7770 posts
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I don't think renaming the Mantra surface to ‘Classic Shader’ makes it deprecated. The classic shader is still supported, and is not very changed from previous iterations. If you want separate controls for everything, or to optimize refract roughness, the power is there.
Technical Discussion » FBX pivot to unity
- jsmack
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Technical Discussion » Exporting cameras from Maya into Houdini
- jsmack
- 7770 posts
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You can't directly see the animation curves for alembic objects. If you really need to, you can use the ‘Object’ CHOP to import transforms as channel data in chops.
Technical Discussion » Exporting cameras from Maya into Houdini
- jsmack
- 7770 posts
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Technical Discussion » OCIO Implementation plan
- jsmack
- 7770 posts
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I discovered a hacky work around. If you make a new color space with your look transforms, you can make a view with that bogus space as the destination. As for setting the houdini environment to not export OCIO, this difficult, as tools that exist in the hou environment might rely on ocio. I'll have to figure something hout.
Technical Discussion » OCIO Implementation plan
- jsmack
- 7770 posts
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OCIO profiles are still mostly non-functional in the latest cut of 16.0. Only transforms without looks seem to work, and even then only sometimes, such as mplay being somewhat broken. As all production displays will contain looks, the implementation is not usable in it's current state. Is OCIO planned to be usable in 16.0, or only in a future version?
Until then, is there a way to disable the OCIO profile being referenced? I would rather that the LUT exported by the environment be used. It seems that the exported OCIO path takes precedence.
Thanks,
Jonathan Mack
Until then, is there a way to disable the OCIO profile being referenced? I would rather that the LUT exported by the environment be used. It seems that the exported OCIO path takes precedence.
Thanks,
Jonathan Mack
Technical Discussion » Exporting cameras from Maya into Houdini
- jsmack
- 7770 posts
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That won't work. You can only import geometry that way. Use the alembic archive object for a quick and dirty way to bring in an alembic camera. It is not a great way though, because the camera is created at the bottom of a deep hierarchy, and makes using it cumbersome.
Houdini Indie and Apprentice » Displacement mapped mesh taking longer than high poly original mesh to render?
- jsmack
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Houdini Learning Materials » Q: mantra output file name variables?
- jsmack
- 7770 posts
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I don't see why you wouldn't be able to do that with an expression in houdini. There isn't really a direct parallel to renderlayer from maya, but the closest is probably the rop itself, or maybe takes, you can put either in the file name easily. Putting the camera name in is fairly simple too. It's up to you to create variables that represent file locations of interest. In your environment, export variables as needed to build your path. Most production pipelines will have scripted environments containing variables representing every little bit of metadata, and some use python modules for path construction.
for example:
on a rop named smoke_bty:
using exports:
you would probably want to build a set of scripts for automating the creation of such variables, and even updating them when the scene file is saved. Some variables such as version/scene name, could be extracted directly from the scene file name using regex.
If you want the render pass name in the file name, I think you can do that using the extra image planes list, and enabling ‘different file’. This allows for a unique path for each image plane.
Another option to try is “Extract Image Planes” option (add from render properties). I haven't experimented with this option, but I know this is used by the baking tools.
for example:
on a rop named smoke_bty:
camera = "/obj/sc0034_trackcam_mp1" vm_picture = $SHOT_PATH/image/$TASK/${SHOT}_${TASK}_${SCENE_NAME}_${OS}_v`padzero(4,$VER)`/`opname(chsop('camera'))`-${RESNAME}_${COLORSPACE}_exr/${SHOT}_${TASK}_${SCENE_NAME}_${OS}_v`padzero(4,$VER)`-`opname(chsop('camera'))`-${RESNAME}_${COLORSPACE}.$F4.exr
using exports:
/ -> setenv VER=1 / -> setenv TASK="fx-smoke" / -> setenv SCENE_NAME = "shipcrash" / -> setenv RESNAME = "3kred" / -> setenv COLORSPACE = "acescg" / -> setenv SHOT_PATH = "F:/data/projects/coolvfx/sc0034" / -> setenv SHOT = "sc0034"
If you want the render pass name in the file name, I think you can do that using the extra image planes list, and enabling ‘different file’. This allows for a unique path for each image plane.
Another option to try is “Extract Image Planes” option (add from render properties). I haven't experimented with this option, but I know this is used by the baking tools.
Edited by jsmack - March 12, 2017 14:09:03
Houdini Learning Materials » What is the best way to make a realistic grass field in Houdini 16?
- jsmack
- 7770 posts
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ndickson
Has anyone done tall grass, namely multi-blade grass? A few years back, (just for fun), I got part way through making a few assets for generating the geometry for grass of various types and levels of detail, including some ludicrously high-res hero grass, but I never got around to cleaning it up and making it usable, and I never finished getting the topology right for the connections between the blades on multi-blade grass.
If you're primarily interested in lawn grass, the next level of detail would be that there's a central fold in each blade, which could be faked by adjusting normals across the width of the blades in the shader if you're not zooming in very close. Lawn grass also usually has 2 blades coming from each plant, with a nearly-white base right around ground level, but I found that those are almost impossible to see in a real lawn from above. There are also tiny striations along the length of each blade, but they're pretty hard to see directly on lawn grass unless you're looking for them; they're much more obvious in tall grass. However, they do make shiny blades of lawn grass have very anisotropic shininess.
I've done tall grass/corn for features such as divergent and jupiter ascending, and it was based on a ‘transform pieces’ workflow, where all the blades/stalks/seeds/tassel are created at once, and then transformed by a point cloud. For distant plants, the leaves were represented as curves, and the seeds as particles. Now that for loops/compiled blocks/packed primitives exist, this could probably be done far more efficiently.
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