I have a render plus a depth map created in other software - where / how do I plug it into Mantra (and set the black/white distances) so it knows when to occlude stuff? I need to add clouds/fog to an existing render.
Sorry, I'm sure this is ultra-basic, but googling only seems to bring up how to create depth maps, not how to use them within Houdini.
It's just plain ole' Z-depth (EXR sequence), not a DCM.
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Houdini Indie and Apprentice » How to use (as opposed to create) a z-depth map with Mantra?
- howiem
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Houdini Indie and Apprentice » How to get an obj's world pos in a nice expression-friendly way (say for driving a particle source from a null)?
- howiem
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… and right now less clicks = more likely to get home on time. But I promise to learn the constraint approach. Thanks!
Houdini Indie and Apprentice » How to get an obj's world pos in a nice expression-friendly way (say for driving a particle source from a null)?
- howiem
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Oh my goodness. That's wonderful. Thanks a million
And no, I wouldn't have liked to type this by hand (let alone copy and paste and tweak for Y and Z):
Crikey - I didn't know you could stuff that much code in one of those tiny little boxes either
And no, I wouldn't have liked to type this by hand (let alone copy and paste and tweak for Y and Z):
{ matrix src_xform = optransform("../MY_NULL"); matrix target_xform_inverted = invert(optransform(opinputpath(".", 0))); matrix final_xform = src_xform * target_xform_inverted; matrix rest_xform = identity(4); matrix self_xform = rest_xform * final_xform; float result = explodematrixpr( self_xform, vector3(ch("./px"), ch("./py"), ch("./pz")), vector3(ch("./prx"), ch("./pry"), ch("./prz")), chs("./xOrd"), chs("./rOrd"), "TX"); return result; }
Crikey - I didn't know you could stuff that much code in one of those tiny little boxes either
Houdini Indie and Apprentice » Handling Large Volumes
- howiem
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I don't think RS supports anything other than density for volumes - there doesn't seem to be any way to use textures. (boo) … I'd love to hear if I'm wrong
Houdini Indie and Apprentice » point vop requires polygon density: other option?
- howiem
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You can use a texture map instead, if that suits, and use a COP net to generate the mask.
Houdini can handle masses of points, though, so it may be worth just using a high res mesh - plus it lets you add things like the Paint SOP to tweak density after the VOP if you need it.
Alternatively look into the Heightfield tools..? There's an HF Scatter sop precisely for terrain use
Houdini can handle masses of points, though, so it may be worth just using a high res mesh - plus it lets you add things like the Paint SOP to tweak density after the VOP if you need it.
Alternatively look into the Heightfield tools..? There's an HF Scatter sop precisely for terrain use
Houdini Indie and Apprentice » Scatter objects on the center edges of another and aligned to that also.
- howiem
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Newb here, too. Pleased to meet you
Not quite clear on why you want to scatter - Scatter op is usually when you want randomness to the points' positions.
One issue you'll have is that in a poly (geodesic) sphere the edges aren't all the same length.
Had a quick play, though; definitely not there yet, but there might be some clues in there. Note the use of Poly Frame, with the Tangent attribute changed to N - this gives you normals that are actually tangential. Also the use of primpoints in the Group Expression to find all the points connected to only 4 others (which happen to be the structure's midpoints)
There are issues (rotation of some of the tubes is wrong) but I ran out of time.
Suspect if you're trying to create a tent you may be best off with a poly wire approach, then add stuff to the points after. (Note the weirdness: to delete all the primitives in a bit of geometry, but leave the points, you need to use the Add SOP. That's Houdini for you
Not quite clear on why you want to scatter - Scatter op is usually when you want randomness to the points' positions.
One issue you'll have is that in a poly (geodesic) sphere the edges aren't all the same length.
Had a quick play, though; definitely not there yet, but there might be some clues in there. Note the use of Poly Frame, with the Tangent attribute changed to N - this gives you normals that are actually tangential. Also the use of primpoints in the Group Expression to find all the points connected to only 4 others (which happen to be the structure's midpoints)
There are issues (rotation of some of the tubes is wrong) but I ran out of time.
Suspect if you're trying to create a tent you may be best off with a poly wire approach, then add stuff to the points after. (Note the weirdness: to delete all the primitives in a bit of geometry, but leave the points, you need to use the Add SOP. That's Houdini for you
Houdini Indie and Apprentice » How to get an obj's world pos in a nice expression-friendly way (say for driving a particle source from a null)?
- howiem
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If you want a Particle Source to follow a Null, you can just stick
(etc) into the Position boxes.
But that'll only work if the Null itself is animated/translated. If it's parented to something else, you'll just getout. So how do I get the Null object's position in world space? I've found optransform(), but it doesn't seem very stuff-it-in-a-parameter-as-an-expression-friendly, if you get me.
(And whenever you're controlling something's location/rotation with expressions, you always end up with three separate copies of your expression as Vectors are always broken out into separate axes in the UI, when often it would be easier to be able to just use a Vector. Is there any way to have Houdini kinda munge translation or rotation parameters into a nice single expression-friendly Vector type box?)
ch("/obj/MY_NULL/tx")
But that'll only work if the Null itself is animated/translated. If it's parented to something else, you'll just get
{0,0,0}
(And whenever you're controlling something's location/rotation with expressions, you always end up with three separate copies of your expression as Vectors are always broken out into separate axes in the UI, when often it would be easier to be able to just use a Vector. Is there any way to have Houdini kinda munge translation or rotation parameters into a nice single expression-friendly Vector type box?)
Technical Discussion » after effect camera to Houdini
- howiem
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Note that in AE, zoom and focal length and film size are all interlinked. You can ignore the zoom parameter - adjust the other two values and “zoom” will adjust automatically.
I created a couple of kludgy scripts to import AE data into Houdini, and export Houdini data out for AE (see https://gist.github.com/howiemnet [gist.github.com] )
The nice thing about AE is that you when you copy a bunch of keyframes to the clipboard, they're just text - you can open a text editor and paste them in to see. And likewise, as long as you keep the format the same, you can create a text file with AE keyframe data, and just paste it onto a layer… tada, keyframes.
Drop me a pm if you need further help.
I created a couple of kludgy scripts to import AE data into Houdini, and export Houdini data out for AE (see https://gist.github.com/howiemnet [gist.github.com] )
The nice thing about AE is that you when you copy a bunch of keyframes to the clipboard, they're just text - you can open a text editor and paste them in to see. And likewise, as long as you keep the format the same, you can create a text file with AE keyframe data, and just paste it onto a layer… tada, keyframes.
Drop me a pm if you need further help.
Technical Discussion » How to approach smoke sims / volumes where you need varying levels of detail?
- howiem
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I have a scene with a camera moving in from a wide shot of dry ice across a floor into the source of the dry ice.
I've solved it for now in a kludgy way - I'm fixing it in post (ha!) - two separate sims, one big low-res, one much smaller high-res, and I'm dissolving between them as the camera moves in.
But I'd like to know how this ought to be approached.
To make things extra difficult, I'm using Redshift, so I don't have access to any sexy render-time vol displacement, or 3D noise textures - just density.
My limited understanding of VDBs suggests they'd be great for storing the smoke; less voxels / data for the main coverage, then finer detail for the tight end of the shot. But I'm not sure how you'd approach the actual sim.
Possible option - chop out a chunk of the low-res volume, feed that into a higher-res sim to add some noise / disturbance (?)
What would be the best approach? Any suggestions for googling? Or do you just suck it up and sim everything at the highest res you need (and maybe downres parts of it later to ease rendering times?)
I've solved it for now in a kludgy way - I'm fixing it in post (ha!) - two separate sims, one big low-res, one much smaller high-res, and I'm dissolving between them as the camera moves in.
But I'd like to know how this ought to be approached.
To make things extra difficult, I'm using Redshift, so I don't have access to any sexy render-time vol displacement, or 3D noise textures - just density.
My limited understanding of VDBs suggests they'd be great for storing the smoke; less voxels / data for the main coverage, then finer detail for the tight end of the shot. But I'm not sure how you'd approach the actual sim.
Possible option - chop out a chunk of the low-res volume, feed that into a higher-res sim to add some noise / disturbance (?)
What would be the best approach? Any suggestions for googling? Or do you just suck it up and sim everything at the highest res you need (and maybe downres parts of it later to ease rendering times?)
Technical Discussion » How do you guys manage big scenes with many objects? I'm struggling.
- howiem
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Oooo… groups. Cool, thanks, Daryl.
The trouble with Houdini's docs / training isn't the wealth of resources available - I've waded gleefully through a couple of hundred hours' tutorials in my couple of months with Houdini - it's the lack of a roadmap to ensure you get through - and absorb - the basics. Thank you for your patience, folks
The trouble with Houdini's docs / training isn't the wealth of resources available - I've waded gleefully through a couple of hundred hours' tutorials in my couple of months with Houdini - it's the lack of a roadmap to ensure you get through - and absorb - the basics. Thank you for your patience, folks
Technical Discussion » How do you guys manage big scenes with many objects? I'm struggling.
- howiem
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Well if that doesn't look like exactly what I asked for. Thank you, Matthias, much appreciated.
* * *
layer management objects grouping groups visibility bundles layers scene management render layers
* * *
layer management objects grouping groups visibility bundles layers scene management render layers
Technical Discussion » How do you guys manage big scenes with many objects? I'm struggling.
- howiem
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Just to add:
Houdini gives you all the tools you'd need to create the perfect layer-management system. And if you're doing the sort of job where you could be spending weeks on a single scene, you may well be happy enough spending a few hours setting up a node with all the switches you need - heck, you might be happy just diving into a textport and switching stuff on and off with sneaky custom commands.
So rolling your own management setup is absolutely possible. But then you could roll your own “Takes” functionality if you wanted, but SideFX decided it was worth providing a pre-built one for us.
I don't want to spend time rolling my own “Layers” functionality if someone's already done it… no point reinventing the wheel. So is there one out there already I can leverage?
Or are there any other cheeky tips'n'tricks built into H that I as a noob may have missed?
Houdini gives you all the tools you'd need to create the perfect layer-management system. And if you're doing the sort of job where you could be spending weeks on a single scene, you may well be happy enough spending a few hours setting up a node with all the switches you need - heck, you might be happy just diving into a textport and switching stuff on and off with sneaky custom commands.
So rolling your own management setup is absolutely possible. But then you could roll your own “Takes” functionality if you wanted, but SideFX decided it was worth providing a pre-built one for us.
I don't want to spend time rolling my own “Layers” functionality if someone's already done it… no point reinventing the wheel. So is there one out there already I can leverage?
Or are there any other cheeky tips'n'tricks built into H that I as a noob may have missed?
Edited by howiem - 2018年1月21日 06:33:45
Technical Discussion » How do you guys manage big scenes with many objects? I'm struggling.
- howiem
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When you have lots of objects in your scene, you can group them nicely in the Network views, stick ‘em in those frame thingies etc - but controlling viewport visibility, and separating things into layers for rendering - well, it all seems a bit crude.
Seems the only way to, say, group objects you want to render together, is to name them in such a way you can use wildcards in the Candidate Objects field. Feels a bit kludgy. And can trip you up. (Oops, I’m accidentally rendering my sim object as well as my cached import)
I'd love the sort of layer management that 3dsmax provides - nameable layers of objects you can switch on and off; even Blender with its old-fashioned 20 un-nameable layers approach is better than nothing.
I gather that Houdini is traditionally used in a large studio environment where they'll have invested in creating their own purpose-built managers to handle this sort of thing, where necessary - and the chances are they won't need them much of the time as Houdini is less likely to used for creating “whole scenes”, rather it's used for adding elements to scenes created and assembled in other software.
Are there any scripts / techniques / third-party plugins I can leverage to wrangle my scenes?
Seems the only way to, say, group objects you want to render together, is to name them in such a way you can use wildcards in the Candidate Objects field. Feels a bit kludgy. And can trip you up. (Oops, I’m accidentally rendering my sim object as well as my cached import)
I'd love the sort of layer management that 3dsmax provides - nameable layers of objects you can switch on and off; even Blender with its old-fashioned 20 un-nameable layers approach is better than nothing.
I gather that Houdini is traditionally used in a large studio environment where they'll have invested in creating their own purpose-built managers to handle this sort of thing, where necessary - and the chances are they won't need them much of the time as Houdini is less likely to used for creating “whole scenes”, rather it's used for adding elements to scenes created and assembled in other software.
Are there any scripts / techniques / third-party plugins I can leverage to wrangle my scenes?
Technical Discussion » What causes these bokeh artifacts and how do I cure them? Should this be RFE'd?
- howiem
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Thank you! That's sorted it! Even at 5x5 Pixel samples, as per previous images, that's sooooo much better.
I can up the sampling a bit more, but even with this level of noise, my de-noising plugin can tidy it up - something it couldn't do with the blotchy artifacts from before.
Yay
So - I wonder - under what circumstances does the correlated samples thingy actually benefit you?
I can up the sampling a bit more, but even with this level of noise, my de-noising plugin can tidy it up - something it couldn't do with the blotchy artifacts from before.
Yay
So - I wonder - under what circumstances does the correlated samples thingy actually benefit you?
Edited by howiem - 2018年1月21日 05:45:13
Technical Discussion » What causes these bokeh artifacts and how do I cure them? Should this be RFE'd?
- howiem
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Nope - my bad. Pixel Samples does cure it, though you need to whack it right up (32x32 seems good):
Leaving this post here for future reference; may help someone else. Never realised I'd need so many Pixel samples.
Leaving this post here for future reference; may help someone else. Never realised I'd need so many Pixel samples.
Houdini Learning Materials » Request: Guide to setting up a simple render farm for us Indie users
- howiem
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I've got multiple machines - Macs and PCs - but I've struggled to understand the hQueue docs, and a step-by-step guide for one-man-bands and small studios would be ace.
This was very simple with other 3D packages (just load the same scene on all machines, point them all at the same output folder, have them all skip existing frames, set them all going) but Mantra only seems to check for existing frames when you hit Go, and not after each frame is complete, so the machines all end up rendering the same frames as each other.
This was very simple with other 3D packages (just load the same scene on all machines, point them all at the same output folder, have them all skip existing frames, set them all going) but Mantra only seems to check for existing frames when you hit Go, and not after each frame is complete, so the machines all end up rendering the same frames as each other.
Technical Discussion » What causes these bokeh artifacts and how do I cure them? Should this be RFE'd?
- howiem
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This is plaguing me. I've created a super-simple scene to illustrate: just a particle emitter with the constant shader attached, and a camera.
Rendered with just depth of field enabled:
Rendered with just motion blur:
But with both, everything goes splotchy:
Doesn't seem to be related to Pixel Samples, or Geo Time Samples. How do I cure it?
Rendered with just depth of field enabled:
Rendered with just motion blur:
But with both, everything goes splotchy:
Doesn't seem to be related to Pixel Samples, or Geo Time Samples. How do I cure it?
Edited by howiem - 2018年1月19日 06:52:52
Technical Discussion » H16.0 - Autosave is automatically disabled on startup - is there any way to stop / override this behaviour?
- howiem
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Apologies if this is addressed in 16.5 - I'm not in a position to install it for now.
I'm often crashing Houdini (that'll teach me to stick a sexy new GTX1080Ti in an old Mac Pro I guess)… but often forget to enable Autosave. Much of the time H managed to save a copy of the scene in /tmp, but not always.
Is there a way to automatically enable autosave when H loads? Some sneaky script I can stuff somewhere?
I'm often crashing Houdini (that'll teach me to stick a sexy new GTX1080Ti in an old Mac Pro I guess)… but often forget to enable Autosave. Much of the time H managed to save a copy of the scene in /tmp, but not always.
Is there a way to automatically enable autosave when H loads? Some sneaky script I can stuff somewhere?
Technical Discussion » Object names in input files
- howiem
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You can completely automate this sort of stuff with Python in Houdini. This script doesn't do what you want, but it may give you some clues as to how to attack the problem, as it demonstrates how to open a file and read the lines out: https://gist.github.com/howiemnet/8784cf04568c849271730965eaf35159 [gist.github.com]
Technical Discussion » Multi select in the curve SOP for 2018... please?
- howiem
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Agreed. It's a pain at the moment. Have you logged this as an RFE? If not –> https://www.sidefx.com/bugs/submit/ [www.sidefx.com]
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