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Solaris and Karma » Unexpected outputs from Karma
- jsmack
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I think those are checkpoint files. You can disable checkpointing and it won't write those files.
Solaris and Karma » Reversed Vertex Ordering - usdexport SOP
- jsmack
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krause_trk
I don't know a lot, but I do know that to get normal tags to populate correctly, inside of Cinema4D (specifically), I need to configure my USD Export to include this -
Blender doesn't require this nor does Keyshot.
That's odd. Doing that breaks the normals attribute for Karma and HoudiniGL views.
Solaris and Karma » Particles + Volumes : Karma CPU and XPU too different
- jsmack
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I can vaguely make out the words "principledshader" and "pyroadvancedshader" in your screenshot, both of which are Mantra materials. Unfortunately, XPU doesn't support Mantra materials. Only Karma and MaterialX materials can be used.
Solaris and Karma » Reversed Vertex Ordering - usdexport SOP
- jsmack
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krause_trk
Cinema4D requires that the normals be "Indexed Attributes" or else the normals just get dropped (other software does not seem to have this requirement).
I don't believe USD supports normals as indexed, they're always per vertex or per point. When I force them to be 'indexed' on the SOP import, it doesn't create normals and instead imports them as a primvar which causes it to be ignored for purposes of shading.
Solaris and Karma » Bucket sizes - how to determin optimal size?
- jsmack
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Soothsayerjsmack
never have I ever changed bucket size
I'm working on a scene where an image rendered with 32 pixel bucket has nearly double the render time of a 16 pixel bucket. Plenty of ram left on both settings, so I'm wondering what's going on.
Is that with Mantra? I experimented with bucket size with mantra and never saw a pattern. some scenes were faster with bigger buckets others slower--so I left at default. What render time spread are you seeing at 2x, 5 seconds vs 10 seconds or 1 hour vs 2 hours?
Solaris and Karma » Bucket sizes - how to determin optimal size?
- jsmack
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Solaris and Karma » Triplanar Normal map
- jsmack
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You can't use triplanar mapping with normal maps without some custom implementation. normal maps require tangents, which don't exist when triplanar mapping, so it's not well defined even if you did come up with a custom shader that blended the resulting normals in object space. bump or displacement maps are preferred when using triplanar maps since they don't require any local tangent space to use.
Solaris and Karma » Reversed Vertex Ordering - usdexport SOP
- jsmack
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The usdexport sop documentation is correct. SOP coordsys is left handed and vertex order is left handed. By default when importing SOP geometry to USD, the order is left unchanged and the orientation attribute is set to indicate the handedness. Checking the Reverse Ordering checkbox will reverse the orientation of the geometry on import and the handedness will be indicated as the canonical right handed. Most likely, substance painter is ignoring the orientation metadata and assuming the geometry is right handed.
Edited by jsmack - April 19, 2023 19:58:42
Technical Discussion » Matrix transformations in the VEX function 'fromNDC'
- jsmack
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To go to NDC you need to apply the perspective transform. The camera's matrix doesn't have the perspective matrix, only the positional one. Use the perspective() function to build a perspective matrix. Unfortunately, it doesn't quite use the same parameters as a Houdini camera uses to define the view matrix. The help for the function explains how to convert the values. It also gives an example of using it to build a world to NDC transform.
One odd quirk of perspective transforms is that they are actually four dimensional. The worldtoNDC matrix can't convert a 3d position directly to NDC. Instead, the 3d position is converted to homogeneous coordinates in 4D, and then the perspective is applied in 4D. To get the NDC coordinate, divide the transformed 4d position by its 'w' component, and shift from zero centered to 0.5 centered.
One odd quirk of perspective transforms is that they are actually four dimensional. The worldtoNDC matrix can't convert a 3d position directly to NDC. Instead, the 3d position is converted to homogeneous coordinates in 4D, and then the perspective is applied in 4D. To get the NDC coordinate, divide the transformed 4d position by its 'w' component, and shift from zero centered to 0.5 centered.
Edited by jsmack - April 19, 2023 17:50:51
Houdini Lounge » Anyway to default visualizers to "Marker" instead of "Color"
- jsmack
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JasOnn
I saw that preset option, but that only applies to a specifically named and type of attribute doesnt it?
There arent presets that would affect all visualizers, no matter their attribute name, are there?
The attribute type affects what kind of visualizer to use by default. scalar floats visualize as color ramp, 3-tuple floats as color, normal and vector as vector markers, strings as text markers, integers as random from attribute.
Houdini Indie and Apprentice » How do you Load Payloads at Render Time for Karma
- jsmack
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I'm not sure I follow, the payloads should be loaded at render time unless they've been elided with population masks.
Solaris and Karma » Efficient animation caching from SOPs
- jsmack
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The 'default values' field lists attributes which skip writing time samples and only write a default value.
Solaris and Karma » Efficient animation caching from SOPs
- jsmack
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The sop import LOP has settings that control which attributes write time samples. An equivalent node in SOPs is USDconfigure which records the values of the import settings as detail attributes.
Houdini Indie and Apprentice » Groom workflow questions
- jsmack
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Solaris and Karma » Karma - Disable textures at render time
- jsmack
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am_wilkins
Thanks for the suggestions everyone!
I was hoping Karma had this feature, but it appears not yet.
Will continue trying above suggestions or other workarounds.
Regards,
Andrew
There's a mode that disables shading and lighting, but maybe that's not what you want.
Houdini Lounge » Motion Blur Karma vs Mantra
- jsmack
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jerry7jsmack
Your camera shutter needs the same alignment as the samples...
I added a camera, the problem still existed.
Cache LOP seems to be broken. If I set time samples on the node that creates them, it works fine.
Edit:
This is truly a bizarre issue. The usda files are nearly identical. The only difference is that the cache lop seems to write the time samples with full 64bit precision where as the time samples created on the transform appear to have been 32 bit at some point before recording at 64.
Cache:
0.85: ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, -1.15, 0, 1) ),
1: ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, -1, 0, 1) ),
1.15: ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, -0.8500000000000001, 0, 1) ),
No Cache:
0.8499999940395355: ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, -1.1500000059604645, 0, 1) ),
1: ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, -1, 0, 1) ),
1.1500000059604645: ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, -0.8499999940395355, 0, 1) ),
Edited by jsmack - April 13, 2023 15:54:58
Houdini Lounge » Motion Blur Karma vs Mantra
- jsmack
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jerry7
It still has problems at specific parameters value.
Your camera shutter needs the same alignment as the samples. Without a camera primitive or karma render settings, it will use the default. By specifying time samples in a smaller window than the render, you're telling the object to be stationary for part of the shutter window.
Edited by jsmack - April 13, 2023 01:12:16
Technical Discussion » Orient a bounding box to look-at a target?
- jsmack
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Get the lookat transform and apply the inverse transform so the bound happens in the space of the lookat. Then apply the bounds and forward transform.
Solaris and Karma » hide polygon faces on a geom prim?
- jsmack
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displayOpacity should work, but requires connecting it to opacity in a shader. It doesn't hide them but makes the faces have zero opacity.
Technical Discussion » Material Builder + Bake Texture confusion
- jsmack
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That's expected. Bound attributes on materials do not tunnel when called with shader calls, i.e. the bind node used in the principled shader is not connected to the outer calling shader when layering multiple shaders together. The bind needs to be explicitly connected to the bound input of each shader layer. Due to the point color pin being hidden it's not possible.
To get the point color again, do not use the texture controls on the principled shader. Create a surface color node and set up the texture and point color settings there and connect this node to the principled shader's basecolor input.
To get the point color again, do not use the texture controls on the principled shader. Create a surface color node and set up the texture and point color settings there and connect this node to the principled shader's basecolor input.
Edited by jsmack - April 10, 2023 18:39:13
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