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Houdini Lounge » Modeling primarily in Houdini
- Rebus B
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This may be a problem with the language being used. Instead of calling the network “history” think of it as “structure” which is much more in keeping with Houdini's philosophy and power.
Technical Discussion » More Than One Return Statement in Vex User Defined Function
- Rebus B
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wavebit
I don't think it's a good way to return multiple values. Changing input parameter is danger and hard to debug.
Yes, it is considered poor form in general programming terms. A function that changes input objects introduces what are called (coincidentally?) side effects where the code is making unexpected changes to variables that may not be obvious to the user.
Sure it seems fine if only you are using the code but it remains risky because you may lose track as the thing gets bigger. If you are depending on those values elsewhere and some function is making unannounced changes it will be very hard to track down what is going wrong. That is why the ‘export’ keyword would be used: it does not change how the function behaves it just warns the user that it may change that variable.
Edited by Rebus B - Sept. 17, 2018 12:28:02
Houdini Indie and Apprentice » textport and VEXpression help
- Rebus B
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So “exhelp” command is pretty handy but I am running into many functions used in VEXpression that are not available. For ex. “No installed command matches relbbox” or “No installed expressions match relbbox”. Is there a third help function in addition to “help” and “exhelp” to find quick reference to these functions? Looking up on VEX functions webpage lacks the efficiency of the textport ref.
(On a side note, is there a way to control the giant tooltip window? It tends to obscure the part of the screen I would like to reference. Strangely enough it doesn't show up in the VEX editor to help with the functions missing from text port docs.)
(On a side note, is there a way to control the giant tooltip window? It tends to obscure the part of the screen I would like to reference. Strangely enough it doesn't show up in the VEX editor to help with the functions missing from text port docs.)
Technical Discussion » Name attribute warning ?
- Rebus B
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Wondering the same thing. Thought it might be it was missing the pscale but adding that to prims or points doesn't stop the warning.
Ok. Added attribute promote to copy name from point to primitive level (unchecking delete original) and that fixes it.
Ok. Added attribute promote to copy name from point to primitive level (unchecking delete original) and that fixes it.
Edited by Rebus B - Sept. 14, 2018 20:31:30
Houdini Lounge » Modeling primarily in Houdini
- Rebus B
- 80 posts
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GoetzingerC
trying to make Houdini similar to other applications in this regard would probably lead to horrible Frankenstein workflows
This! Because everyone has their pet ways of doing things from other packages. Packages that were developed to do different aspects of 3d animation, some very narrow in scope, with the highest fidelity and efficiency. How are you going to make them all work in a system that has at its core a different philosophy and therefore resulting structure? IMO this is what is what happened to Maya, where Autodesk is just throwing everything they can buy into the package to keep up with the times without any consideration to how those different tool sets connect to its core.
(edit: watched video and I was saying too much too soon… Maybe Houdini could expand to embrace different workflow, but with care not to lose focus on what works so well.)
Edited by Rebus B - Sept. 11, 2018 18:36:55
Houdini Lounge » What's the difference between $PT and $ID
- Rebus B
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The particle $ID is unique to each particle, even if it dies. The $PT number (or @ptnum) is not. So if you need to tie an action to a specific particle or point regardless of how the points come and go, the @id or $ID is guaranteed to work.
Edited by Rebus B - Sept. 11, 2018 11:33:54
Houdini Indie and Apprentice » quicktime movie export?
- Rebus B
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I see what you mean and it certainly makes sense if you have hundreds of sequences that you know you want to keep. I just find myself more often reviewing say a half dozen or so tests for one part of an effect and only wanting to keep one. Nice to be able to bang out a .mov of it immediately and then toss the rest in the trash.
Houdini Lounge » REPLACED BY?
- Rebus B
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That is good. Having cut my teeth on C code I would miss the semi-colons and curly brackets!
Houdini Indie and Apprentice » quicktime movie export?
- Rebus B
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BabaJ
If your making 100 flipbooks…that's the chunk of time your ‘wasting’…doing conversions doesn't take much longer to add in the process.
Have to agree with NRDPXL here… The point is those 100 flipbooks are taking long enough, not wasting time as it is a requisite activity, it is adding another (optimistic) “not much longer” * 100 that is the time waste when there is/was an easy direct method in place to accomplish the same result.
Thankfully this is not a bug on Windows although ironically qt is showing its age in that OS. I would be stewed if I had to exit the Houdini workflow every time I wanted to preserve a flipbook via qt.
Edited by Rebus B - Sept. 8, 2018 14:08:57
Houdini Lounge » REPLACED BY?
- Rebus B
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In exhelp the requested command's declaration is immediately followed by “REPLACED BY” and a list of I am assuming Python commands that do the same thing.
Is that to be taken as a warning?
Is that to be taken as a warning?
Edited by Rebus B - Sept. 8, 2018 13:46:25
Houdini Indie and Apprentice » Command Exit Code : 3
- Rebus B
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Could it be related to the resolution limit when rendering in Indie? I remember having similar problems (with quick render) when using the Non-Commercial version a while back.
Houdini Indie and Apprentice » scattering sphere on a "Minecraft"surface
- Rebus B
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I believe the droid you are looking for is the Points From Volume SOP.
1) Create a volume from your base shape with an Iso Offset.
2) Plug that into Points From Volume and select a Point Configuration (grid or tetrahedronal)
3) Pipe into point source on a Copy To Points SOP.
1) Create a volume from your base shape with an Iso Offset.
2) Plug that into Points From Volume and select a Point Configuration (grid or tetrahedronal)
3) Pipe into point source on a Copy To Points SOP.
Edited by Rebus B - Sept. 5, 2018 19:21:33
Houdini Indie and Apprentice » Houdini Render Passes/AOVs
- Rebus B
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This page details the info on Image Planes: http://www.sidefx.com/docs/houdini/render/deeprasters.html [www.sidefx.com]
The the key is the basic render passes {diffuse, reflect, refract, sss, etc…} are called Export Components and the active ones for the render are listed out at the top of the Extra Image Planes tab in the Images section of the Mantra render node. A list of the common export components is already in place as the default when you create the Mantra node. Just delete the ones you do not need. Then the source of the render samples for each of those active export components are selected below.
So to get the diffuse and reflection pass with all lighting (direct and indirect) you would have ‘diffuse’ and ‘reflect’ entered in the Export Components field and 'Combined Lighting (per-component)' checked off from the list below. To get passes for the initial rays activate 'Direct Lighting (per-component)' where as 'Indirect Lighting (per-component)' will render the results of the rays bouncing off surfaces. Try a render with all three checked to see the differences.
You can even get render passes per light (as well as many more) by adding Extra Image Planes at the bottom of the Extra Image Planes tab and selecting from the popdown list on the VEX Variable parameter.
All of the active Image Planes will be bundled up into one image file per frame in image formats like EXR that support multiple image planes or can be rendered to separate files for formats that don't. When you render to M-Play with the exr file format you can use the drop down selector at the top left of the M-Play window to see each layer. It is super cool!
The the key is the basic render passes {diffuse, reflect, refract, sss, etc…} are called Export Components and the active ones for the render are listed out at the top of the Extra Image Planes tab in the Images section of the Mantra render node. A list of the common export components is already in place as the default when you create the Mantra node. Just delete the ones you do not need. Then the source of the render samples for each of those active export components are selected below.
So to get the diffuse and reflection pass with all lighting (direct and indirect) you would have ‘diffuse’ and ‘reflect’ entered in the Export Components field and 'Combined Lighting (per-component)' checked off from the list below. To get passes for the initial rays activate 'Direct Lighting (per-component)' where as 'Indirect Lighting (per-component)' will render the results of the rays bouncing off surfaces. Try a render with all three checked to see the differences.
You can even get render passes per light (as well as many more) by adding Extra Image Planes at the bottom of the Extra Image Planes tab and selecting from the popdown list on the VEX Variable parameter.
All of the active Image Planes will be bundled up into one image file per frame in image formats like EXR that support multiple image planes or can be rendered to separate files for formats that don't. When you render to M-Play with the exr file format you can use the drop down selector at the top left of the M-Play window to see each layer. It is super cool!
Houdini Indie and Apprentice » Bullet solver not colliding with imported geometry
- Rebus B
- 80 posts
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A good place to start debugging this would be to see what the collision geometry in the dop network looks like by toggling Show Guide Geometry under the Bullet Data tab on the RBD object that feeds in the imported geo to the network and then try different Geometry Representations to find one that may work better.
Houdini Indie and Apprentice » Where are parameters created in /mat edited?
- Rebus B
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Ah, ok… I know /mat is relatively new and I believe was added to make building out shaders easier… Is there a methodology that works between the two ways of doing things? Do you build out the shader network in /mat and just cut and paste to a SHOP material or is there another way?
Edited by Rebus B - Aug. 29, 2018 18:18:15
Houdini Indie and Apprentice » Where are parameters created in /mat edited?
- Rebus B
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Yes, that exposes the parameter nodes, but those are not the editable fields that the parameter controls. What I am wondering is where the current values' fields are. Like within a VOP SOP where the contained Parameter VOPs and promoted parameters appear as additional editable fields on the VOP SOP above them.
Edited by Rebus B - Aug. 29, 2018 17:02:20
Houdini Indie and Apprentice » Where are parameters created in /mat edited?
- Rebus B
- 80 posts
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For example: Working in the /mat context create a Principled Shader and assign to an object. In the shader's Opacity tab click the gear right of Opacity Scale and select Texture>Checkered. Results in new VEX node connected to opac channel input of a VOP named checkered1 and checkered holes appear in the rendered object as expected. On the checker texture node the parameter fields are dark green, the channel input dots appear as promoted parameters and are referenced like: ch('../blur/float2def1').
Where do those new parameter fields exist?
Looking for them… There is no node above /mat for them to attach to (well there is the scene root “/” but they are not there), they do not appear on the original principled shader or the geometry object it is assigned to. Middle clicking on a channel's input dot and selecting Jump to Input Node does not go anywhere while Expose Input Node just reveals the parameter VOP in /mat.
So how do you edit these new parameters? Since the the channel values are coming in from somewhere else they cannot be changed in the checkered1 node. Is the only way to Delete Channels on each one and do it in the VOP node? (and as a corollary how do you gather all the shader channels you would want to expose for editing in one place?)
Where do those new parameter fields exist?
Looking for them… There is no node above /mat for them to attach to (well there is the scene root “/” but they are not there), they do not appear on the original principled shader or the geometry object it is assigned to. Middle clicking on a channel's input dot and selecting Jump to Input Node does not go anywhere while Expose Input Node just reveals the parameter VOP in /mat.
So how do you edit these new parameters? Since the the channel values are coming in from somewhere else they cannot be changed in the checkered1 node. Is the only way to Delete Channels on each one and do it in the VOP node? (and as a corollary how do you gather all the shader channels you would want to expose for editing in one place?)
Technical Discussion » Mountain not displacing curve on z-axis
- Rebus B
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Drawing a curve, all points on z-axis. Want to disturb points using Mountain SOP. Nothing happens!
Moving a single point on curve off of z-axis by tiny fraction (0.00000000001) and it performs as expected.
Thought it may have been related to grid snapping but second curve created manually shows same behavior.
Hmmm… a little more testing: adding normals to original curve via Attribute Wrangle and Mountain works. So it looks like Mountain depends on either implicit or explicit normals to function.
Is this expected behavior?
Moving a single point on curve off of z-axis by tiny fraction (0.00000000001) and it performs as expected.
Thought it may have been related to grid snapping but second curve created manually shows same behavior.
Hmmm… a little more testing: adding normals to original curve via Attribute Wrangle and Mountain works. So it looks like Mountain depends on either implicit or explicit normals to function.
Is this expected behavior?
Edited by Rebus B - Aug. 28, 2018 10:09:59
Technical Discussion » change of a specific field from simulation in geometry
- Rebus B
- 80 posts
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Not sure what you mean by geomagnetics but if you need a surface for it/them you can use the Convert Volume SOP to get one.
Or if you need to move volume data into an existing set of geometry points you can use the Attribute from Volume SOP.
Or if you need to move volume data into an existing set of geometry points you can use the Attribute from Volume SOP.
Edited by Rebus B - Aug. 14, 2018 15:12:54
Technical Discussion » Problem with Pyro Shader Shadows
- Rebus B
- 80 posts
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Thanks jsmack… that is good to know and glad its not broken.
But wait… if it is subtractive than wouldn't the hue be inverted as well as the intensity? If you subtract a blue tinted shadow color from white light, you should wind up with yellow shadows (R+G remain.)
Anyway, just glad to have confirmation its operating as expected. I could have sworn that it was doing the reverse at one point but it must have been my assuming the pyro shadow color would work the same as with lights.
But wait… if it is subtractive than wouldn't the hue be inverted as well as the intensity? If you subtract a blue tinted shadow color from white light, you should wind up with yellow shadows (R+G remain.)
Anyway, just glad to have confirmation its operating as expected. I could have sworn that it was doing the reverse at one point but it must have been my assuming the pyro shadow color would work the same as with lights.
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