Hey!
Say I want to find all the parameters that reference $FSTART. How could I do it?
Thanks!
Anson
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Technical Discussion » How to find all references to a specific special variable
- AnsonSavage
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Technical Discussion » What is the point of the geohandle on setpointattrib
- AnsonSavage
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Ah, I think I found the answer. From the documentation:
"A handle to the geometry to write to. Currently the only valid value is 0 or geoself, which means the current geometry in a node. (This argument may be used in the future to allow writing to other geometries.)"
"A handle to the geometry to write to. Currently the only valid value is 0 or geoself, which means the current geometry in a node. (This argument may be used in the future to allow writing to other geometries.)"
Technical Discussion » What is the point of the geohandle on setpointattrib
- AnsonSavage
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Hi!
Reading the documentation [www.sidefx.com] for the
I'm confused though. Why would setting it to anything other 0 be useful? I don't see how those values could be retrieved, because the output of the wrangle only comes from geohandle 0, right?
Maybe I'm missing something, but a friend just asked me this question and it made me think a bit, haha.
Thanks!
Anson
Reading the documentation [www.sidefx.com] for the
setpointattrib
function, we see that the first input in its signature is geohandle
:int setpointattrib(int geohandle, string name, int point_num, <type>value, string mode="set")
I'm confused though. Why would setting it to anything other 0 be useful? I don't see how those values could be retrieved, because the output of the wrangle only comes from geohandle 0, right?
Maybe I'm missing something, but a friend just asked me this question and it made me think a bit, haha.
Thanks!
Anson
Edited by AnsonSavage - March 22, 2024 11:30:49
Solaris and Karma » instance lights
- AnsonSavage
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bonjarry
Does this apply to "nested instancing" as well?
For example, I set up a car with lights scattered throughout using the "reference" method.
Then I want to instance that car around using a point instancer.
I'm finding that I only get a set of lights on one of the instances and not all.
I'm having exactly the same issue right now We're looking into using for loops?
Solaris and Karma » Getting curved motion blur (substeps?) in Solaris
- AnsonSavage
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robp_sidefxAnsonSavage
if I have a pop sim that I'm instancing some geo on and then I SOP import that into Solaris, I'm looking for the ability to USD Rop it out with the needed substeps. The SOP context had all the substeps I need, but I'm not sure how to put them into the USD.
If using SOP Import then I'd consider a setup like the attached hip where you split the SOP import off to the side in its own branch, specifically Cache that branch with a bunch of substeps, and then Merge those time samples into the rest of your scene.
Hey, this fixed it! Thanks so much!
Edited by AnsonSavage - Feb. 5, 2024 15:50:32
Solaris and Karma » Getting curved motion blur (substeps?) in Solaris
- AnsonSavage
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Okay neat, thank you for the responses.
So, if I have a pop sim that I'm instancing some geo on and then I SOP import that into Solaris, I'm looking for the ability to USD Rop it out with the needed substeps. The SOP context had all the substeps I need, but I'm not sure how to put them into the USD.
Would it be by lowering this `inc` value to something below 1? I'm going to try it and see if it does what I need.
Thanks again!
So, if I have a pop sim that I'm instancing some geo on and then I SOP import that into Solaris, I'm looking for the ability to USD Rop it out with the needed substeps. The SOP context had all the substeps I need, but I'm not sure how to put them into the USD.
Would it be by lowering this `inc` value to something below 1? I'm going to try it and see if it does what I need.
Thanks again!
Solaris and Karma » Getting curved motion blur (substeps?) in Solaris
- AnsonSavage
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Hi!
I'm working on a film that has a lot of leaves on the ground that get blown around in a kind of twirly motion.
The animated leaves are pulled in from a USD. When we enable motion blur, quick moving leaves are streaked out, like the one pointed to here:
The streaking motion blur doesn't properly express the correct motion of the leaves, which is more circular. How would I handle this in Solaris? Do I need to somehow export the animated leaves with substeps? If so, how? (And after doing so, I'm assuming I'd also need to increase the cache substeps?)
Thanks!
Anson
I'm working on a film that has a lot of leaves on the ground that get blown around in a kind of twirly motion.
The animated leaves are pulled in from a USD. When we enable motion blur, quick moving leaves are streaked out, like the one pointed to here:
The streaking motion blur doesn't properly express the correct motion of the leaves, which is more circular. How would I handle this in Solaris? Do I need to somehow export the animated leaves with substeps? If so, how? (And after doing so, I'm assuming I'd also need to increase the cache substeps?)
Thanks!
Anson
Solaris and Karma » Exclusive primitive selection pattern
- AnsonSavage
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Solaris and Karma » Exclusive primitive selection pattern
- AnsonSavage
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Hi! Thank you so much
Okay, this one does work like I expect, which is great!
In our application, we will have some geo that is parallel to /geo (well, actually we are hoping to do this for the entire anim primitive, so we'll have geo that's parallel to /letty), and the following expression didn't seem to do the trick for some reason.
Any thoughts on that?
Thanks so much for the help and the explanations, that makes a lot of sense.
Okay, this one does work like I expect, which is great!
tamte/scene/anim/letty/geo/* - /scene/anim/letty/geo/tempGeo
In our application, we will have some geo that is parallel to /geo (well, actually we are hoping to do this for the entire anim primitive, so we'll have geo that's parallel to /letty), and the following expression didn't seem to do the trick for some reason.
tamte/scene/anim/letty/** - /scene/anim/letty/geo/tempGeo**
Any thoughts on that?
Thanks so much for the help and the explanations, that makes a lot of sense.
Solaris and Karma » Exclusive primitive selection pattern
- AnsonSavage
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Hi!
I have these primitives that I need to unpack in a sop modify. I want to unpack all of the primitives except for the ones under tempGeo.
(The tempGeo is the hair):
So, I figured I'd construct a sop modify that selects all the primitives except for those under tempGeo:
However, I found that inside the SOP Modify, the hair is still unpacked:
If I explicitly select all the primitives except for tempGeo (such that it's a really long pattern like this:
However, I want to make the expression flexible such that if more primitives are added, they are still unpacked, but the tempGeo ones are not. What am I missing?
I've also tried exclusions in collections, but with the same results.
Thanks!
Anson
I have these primitives that I need to unpack in a sop modify. I want to unpack all of the primitives except for the ones under tempGeo.
(The tempGeo is the hair):
So, I figured I'd construct a sop modify that selects all the primitives except for those under tempGeo:
/scene/anim/letty/* - /scene/anim/letty/geo/tempGeo/*
However, I found that inside the SOP Modify, the hair is still unpacked:
If I explicitly select all the primitives except for tempGeo (such that it's a really long pattern like this:
/scene/anim/letty/geo/catchLight_L /scene/anim/letty/geo/catchLight_R /scene/anim/letty/geo/cornea /scene/anim/letty/geo/eyelashes /scene/anim/letty/geo/eyes
etc...), it does work:However, I want to make the expression flexible such that if more primitives are added, they are still unpacked, but the tempGeo ones are not. What am I missing?
I've also tried exclusions in collections, but with the same results.
Thanks!
Anson
Edited by AnsonSavage - Jan. 30, 2024 13:20:01
Solaris and Karma » Overriding Unpacked Primitives
- AnsonSavage
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Hi!
I'm working on a film where we have animation USDs exported from Maya with temp hair and cloth. The CFX department then overrides the hair and cloth primitives with the simulation geometry, and thus we maintain the materials and the USD set-up.
However, Maya doesn't add point velocities on export (if we could figure out how to do that, it would be great of course, so if anyone knows, let me know). So, in order to get proper motion blur, the lighting department is having to unpack the entire /anim primitive and use a trail to add point velocities. This is becoming prohibitively slow (around an hour for 35 frames, and it will often seg-fault just a few frames before it finishes). So we'd prefer to add point velocities earlier in the pipeline so that we don't have to do it every time we want to submit a render.
If the animation department uses a SOP modify in Solaris to add point velocities to the animation, all the primitives under the /anim primitive seem to stay the same, however the CFX department is no longer able to override the temp geo (it simply doesn't work..., there are no error hints or anything that indicate what might be going on).
Any thoughts on our workflow? Are there some settings that we're missing?
Thanks!
Anson
I'm working on a film where we have animation USDs exported from Maya with temp hair and cloth. The CFX department then overrides the hair and cloth primitives with the simulation geometry, and thus we maintain the materials and the USD set-up.
However, Maya doesn't add point velocities on export (if we could figure out how to do that, it would be great of course, so if anyone knows, let me know). So, in order to get proper motion blur, the lighting department is having to unpack the entire /anim primitive and use a trail to add point velocities. This is becoming prohibitively slow (around an hour for 35 frames, and it will often seg-fault just a few frames before it finishes). So we'd prefer to add point velocities earlier in the pipeline so that we don't have to do it every time we want to submit a render.
If the animation department uses a SOP modify in Solaris to add point velocities to the animation, all the primitives under the /anim primitive seem to stay the same, however the CFX department is no longer able to override the temp geo (it simply doesn't work..., there are no error hints or anything that indicate what might be going on).
Any thoughts on our workflow? Are there some settings that we're missing?
Thanks!
Anson
Edited by AnsonSavage - Jan. 24, 2024 13:01:18
Technical Discussion » Configuring RBD Constraints for Tire Rotation & Suspension
- AnsonSavage
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Hi! I've been following this [www.youtube.com] tutorial on how to set up vehicle destruction with RBDs. It's been cool!
After generating the proxy geo for the tires, I'm having trouble figuring out how he creates the points for attaching the wheels to the car.
He briefly explains which constraints he uses at 12:24 in the video, but it's unclear in my mind how he creates the attachment points and how he makes those stick with the rest of the RBD sim.
So basically I'm just trying to figure out how I would attach my proxy wheels to my car to work with all the constraints he mentions. (Also as a note, I'm using the RBD bullet solver as opposed to a vanilla DOP network.)
I'd be grateful for any pointers.
Thanks!
After generating the proxy geo for the tires, I'm having trouble figuring out how he creates the points for attaching the wheels to the car.
He briefly explains which constraints he uses at 12:24 in the video, but it's unclear in my mind how he creates the attachment points and how he makes those stick with the rest of the RBD sim.
So basically I'm just trying to figure out how I would attach my proxy wheels to my car to work with all the constraints he mentions. (Also as a note, I'm using the RBD bullet solver as opposed to a vanilla DOP network.)
I'd be grateful for any pointers.
Thanks!
Solaris and Karma » Separate Materials for Separate Renderers in USD
- AnsonSavage
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rafalOh neat! So if I do that, by default the renderers will figure out which shader applies to it (so shaders containing Pixar nodes will only be rendered in RenderMan, and shaders with Karma nodes will only be rendered in Karma, and all that logic happens under the hood)?
Yes, indeed. Connecting terminal shader nodes to the collect node inside the material library LOP (or to the subnet output inside a subnet VOP) will create two terminal USD shaders inside one USD Material. You bind that one material to geometry. But then when rendering, the Hydra delegate (Karma or RMan) will pick the terminal shader that's appropriate for it.
Thanks!
Anson
Solaris and Karma » Separate Materials for Separate Renderers in USD
- AnsonSavage
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I took a look at this [www.sidefx.com] question in which the idea of setting up separate materials for separate render engines is discussed.
If I have a geometry primitive, how can I create two materials in a material library and make it so one is used for one render engine (e.g., Karma) and the second is used for another render engine (e.g., RenderMan)?
Thanks!
Anson
If I have a geometry primitive, how can I create two materials in a material library and make it so one is used for one render engine (e.g., Karma) and the second is used for another render engine (e.g., RenderMan)?
Thanks!
Anson
Technical Discussion » Camera Motion Blur in Solaris Using Camera Imported From USD
- AnsonSavage
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Technical Discussion » Camera Motion Blur in Solaris Using Camera Imported From USD
- AnsonSavage
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Hi!
I'm using RenderMan, and I set up a little test in Solaris where I compare enabling camera motion blur using a camera sublayered in from a usd and a camera animated in Solaris. Using exactly the same parameters for enabling motion blur, I get the following results:
Using the USD:
Using the Houdini Solaris camera
All I did was switch between the two cameras:
No matter what I've done, I can't figure out how to get the animation to create motion blur with the camera from the USD.
Does it have anything to do with the way timeSamples work?
Are they different from traditional keyframes? What is the best way to get camera motion blur if I'm using a camera sublayered in from USD?
Thanks!
Anson
I'm using RenderMan, and I set up a little test in Solaris where I compare enabling camera motion blur using a camera sublayered in from a usd and a camera animated in Solaris. Using exactly the same parameters for enabling motion blur, I get the following results:
Using the USD:
Using the Houdini Solaris camera
All I did was switch between the two cameras:
No matter what I've done, I can't figure out how to get the animation to create motion blur with the camera from the USD.
Does it have anything to do with the way timeSamples work?
Are they different from traditional keyframes? What is the best way to get camera motion blur if I'm using a camera sublayered in from USD?
Thanks!
Anson
Edited by AnsonSavage - Dec. 15, 2023 18:38:13
Technical Discussion » Creating substep geometry
- AnsonSavage
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pezetko
TimeBlend SOP after File Read SOP is easiest solution to get correct motion blending between frames of imported animation/deformation.
It basically does what Jean Claude Nouchy wrote.
Interesting, I couldn't get it to work with the TimeBlend SOP alone, so I applied VisualCortexLab's solution:
Another solution that seemed to work was to first slow down with a re-time and then speed up with a re-time, keeping substeps at 1 for both (e.g., to add 10 substeps I set speed to 10 on the first one and then 0.1 on the second one)
Houdini Learning Materials » Solaris Tut 5 - Sean Lewkiw: Pruning for Sop Jitter
- AnsonSavage
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Thanks for sharing your fix! I'd be interested in looking at this tutorial series, does it still exist on the internet?
Technical Discussion » Extract position given curvu with VEX
- AnsonSavage
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Hi!
I know I can use the carve node to extract a point along a curve with a curveu input. Can I do the same thing in VEX if the curve is one of the inputs to an attribute wrangle?
I know I can use the carve node to extract a point along a curve with a curveu input. Can I do the same thing in VEX if the curve is one of the inputs to an attribute wrangle?
Technical Discussion » Problem with geometry().freeze()
- AnsonSavage
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queglay
It sounds like it could be similar to locking a node, but I've tried to achieve this behaviour without any luck. Are there any examples that can show its usage? I'm not sure if I'm on the wrong track here for what this function could be used for.
Hey!
Locking an HDA/OTL simply makes it so you can't edit what's inside. Freezing a node with the snow-flake icon saves the geometry data at that node. From my tests, it seems like within an HDA, one can freeze nodes, and this frozen geometry is saved with the HDA.
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