Hi,
I know this post is a bit old but I am messing around with rendering in Mantra with Houdini 16.5.571. I cannot seem to get the Indirect and Direct passes to work correctly for any export components. If you check Direct and Indirect passes it is putting everything into Indirect and nothing goes into Direct. I have turned all of my limits above 1 or a little more just to be sure there were multiple bounces but still, direct pass is empty and it is all fed into indirect. Is this a bug or just the way mantra works now or am I missing something (potentially something very simple that I am overlooking)? I used Mantra before in past versions and it worked fine. I have tried this in a couple different builds as well. (I know was build 16.5.496) Any help is appreciated, thanks!
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Houdini Indie and Apprentice » Houdini Render Passes/AOVs
- Dustin Tarr
- 12 posts
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Technical Discussion » Vellum Dynamic Constraints Question
- Dustin Tarr
- 12 posts
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So I got it to work due to my coworker coming across Rohan Dalvi's recent tutorial [vimeo.com] that I missed where he is able to get it to grab an object and release it.
I was able to use the vellum constraint property node to release it more manually using vex but it is a bit frustrating that to have the object grab the cloth it has to be an actual vellum object within the simulation where the cloth could potentially collide with it. If anyone finds a way to get it to work without the glue object being able to collide with the cloth or vice versa please do not hesitate to post. I will post an example file below of my simple test just in case it is useful to anyone.
I was able to use the vellum constraint property node to release it more manually using vex but it is a bit frustrating that to have the object grab the cloth it has to be an actual vellum object within the simulation where the cloth could potentially collide with it. If anyone finds a way to get it to work without the glue object being able to collide with the cloth or vice versa please do not hesitate to post. I will post an example file below of my simple test just in case it is useful to anyone.
Image Not Found
Edited by Dustin Tarr - Feb. 1, 2019 18:14:36
Technical Discussion » Vellum Dynamic Constraints Question
- Dustin Tarr
- 12 posts
- Offline
Hi all,
I have a Vellum issue I am trying to figure out and not seeing much documentation or information on it out there. I also posted on ODForce so I will link and quote the post below in case the solution comes up in there.
Link:
https://forums.odforce.net/topic/41347-vellum-dynamic-constraints-question/ [forums.odforce.net]
Issue:
“Hello houdini wizards!
I am playing with Vellum and trying to get the dynamic glue constraints to work. The documentation is about 1 very small section and I did what it said to (like creating the glue inside the solver and setting the Create Constraints drop down to Each Frame) but it does not grab the cloth. I played with distances and groups but no luck.
I don't have a specific scenario at the moment so no scene file really that cant be set up in 2 minutes, just a grid as the cloth object, a sphere (fed into the collision input at the sop level) that dips down close the grid and then moves back up. The intention is to have constraints be created to grab the cloth within the set distance, pick it up, pull it, and then release/break the constraints when I want/need to. The breaking I can assume is pretty simple using the broken attribute in the Constraint Properties but I cannot seem to dynamically create constraints to grab the cloth/grid. Any help or knowledge you can give is much appreciated!”
I was unable to find any example files on the subject either but I did see the demo of it being done (https://vimeo.com/313872854) around 24:50. And again, thanks in advance for any advice you can give!
I have a Vellum issue I am trying to figure out and not seeing much documentation or information on it out there. I also posted on ODForce so I will link and quote the post below in case the solution comes up in there.
Link:
https://forums.odforce.net/topic/41347-vellum-dynamic-constraints-question/ [forums.odforce.net]
Issue:
“Hello houdini wizards!
I am playing with Vellum and trying to get the dynamic glue constraints to work. The documentation is about 1 very small section and I did what it said to (like creating the glue inside the solver and setting the Create Constraints drop down to Each Frame) but it does not grab the cloth. I played with distances and groups but no luck.
I don't have a specific scenario at the moment so no scene file really that cant be set up in 2 minutes, just a grid as the cloth object, a sphere (fed into the collision input at the sop level) that dips down close the grid and then moves back up. The intention is to have constraints be created to grab the cloth within the set distance, pick it up, pull it, and then release/break the constraints when I want/need to. The breaking I can assume is pretty simple using the broken attribute in the Constraint Properties but I cannot seem to dynamically create constraints to grab the cloth/grid. Any help or knowledge you can give is much appreciated!”
I was unable to find any example files on the subject either but I did see the demo of it being done (https://vimeo.com/313872854) around 24:50. And again, thanks in advance for any advice you can give!
Edited by Dustin Tarr - Feb. 1, 2019 16:45:27
Houdini Indie and Apprentice » Activating a fractured cloth object by color?
- Dustin Tarr
- 12 posts
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Hello,
I am working on an effect where I am disintegrating an object that is meant to be made of a cloth like material. Currently I have run into an issue where I need pieces of the cloth to break off and float away from point of contact of another object. I figured activating each fractured piece by color in DOPs would be the best route to take but I have not yet found a working method for this through either trial and error nor forums.
My main issue is being able to even get Color into the DOPs to have it control an Activate Value and/or Dynamic Group node. I have seen RBD routes, but those don't seem to work with cloth objects. Most recently I have tried a suggested route with the multisolver and even though this seems to get color into the DOP Network I do not know how to access it since it seems to work a little differently than SOPs.
I have only worked in Houdini for maybe 6 months consistently so I am still new to a lot of it including expressions and python coding. I would very much appreciate any help or suggestions on how I can go about getting this effect to work. I will put up an example file as well. Though it will be prior to the multisolver route because that one is currently not working at all and would not show what I am trying to do. Thank you in advance for any help.
Thanks
I am working on an effect where I am disintegrating an object that is meant to be made of a cloth like material. Currently I have run into an issue where I need pieces of the cloth to break off and float away from point of contact of another object. I figured activating each fractured piece by color in DOPs would be the best route to take but I have not yet found a working method for this through either trial and error nor forums.
My main issue is being able to even get Color into the DOPs to have it control an Activate Value and/or Dynamic Group node. I have seen RBD routes, but those don't seem to work with cloth objects. Most recently I have tried a suggested route with the multisolver and even though this seems to get color into the DOP Network I do not know how to access it since it seems to work a little differently than SOPs.
I have only worked in Houdini for maybe 6 months consistently so I am still new to a lot of it including expressions and python coding. I would very much appreciate any help or suggestions on how I can go about getting this effect to work. I will put up an example file as well. Though it will be prior to the multisolver route because that one is currently not working at all and would not show what I am trying to do. Thank you in advance for any help.
Thanks
Houdini Indie and Apprentice » Automatic Rolling Ball Rig
- Dustin Tarr
- 12 posts
- Offline
Hi guys,
I am currently learning Houdini. I decided to take a break from dynamics for a bit so I am trying to create a rolling ball rig. This may or may not be pretty far outside of my skill level, but I really want to figure out how to get this working.
I've been doing a lot of research on the internet trying to solve the issue of rolling between the X and Z axis. I have my ball rolling fine using hscript between a control's movement/translation that determines a locator's rotation, but once you try to translate diagonally at all between X and Z the rotation starts messing up. I am quickly realizing that hscript will not cut it.
Some have said you have to implement the object's position at the current keyframe, but I would like to avoid having to implement time into this if possible so that I can visually animate and see what is happening as I move it in the viewport.
I have been through a bunch of forums and found one odforce forum post that had a file that used a VOPSOP to calculate the quaternion between a specified axis(es) and angle. Then it muliplied that with the object's point vector. (screencaptures attached)
Forum Link:
http://forums.odforce.net/topic/5415-quaternions-where-to-enter-them/?hl=rolling+cube [forums.odforce.net]
This works relatively well even with multiple axis values, but it does not account for translation. I think I have a theory on how I can get this to work but not enough know how to know where to start, really. I am wondering if you guys may have an idea or suggestion?
How might I get the translation values to determine what percentage of an axis is being used, or faced towards, between 0 and 1? (1 being 100%)
I am currently learning Houdini. I decided to take a break from dynamics for a bit so I am trying to create a rolling ball rig. This may or may not be pretty far outside of my skill level, but I really want to figure out how to get this working.
I've been doing a lot of research on the internet trying to solve the issue of rolling between the X and Z axis. I have my ball rolling fine using hscript between a control's movement/translation that determines a locator's rotation, but once you try to translate diagonally at all between X and Z the rotation starts messing up. I am quickly realizing that hscript will not cut it.
Some have said you have to implement the object's position at the current keyframe, but I would like to avoid having to implement time into this if possible so that I can visually animate and see what is happening as I move it in the viewport.
I have been through a bunch of forums and found one odforce forum post that had a file that used a VOPSOP to calculate the quaternion between a specified axis(es) and angle. Then it muliplied that with the object's point vector. (screencaptures attached)
Forum Link:
http://forums.odforce.net/topic/5415-quaternions-where-to-enter-them/?hl=rolling+cube [forums.odforce.net]
This works relatively well even with multiple axis values, but it does not account for translation. I think I have a theory on how I can get this to work but not enough know how to know where to start, really. I am wondering if you guys may have an idea or suggestion?
How might I get the translation values to determine what percentage of an axis is being used, or faced towards, between 0 and 1? (1 being 100%)
Technical Discussion » Geo Light Issue
- Dustin Tarr
- 12 posts
- Offline
Hello,
I am having an issue in Houdini 15 (latest Build 15.0.347) where the Geo Light is not emitting light when I give it a material. I have found a couple possible problem areas, but still do not understand what the real issue might be that's causing this.
I have it set up so that the Geo Light is using a grid object, as well the same material as that grid (glowing cracks), to emit the light. When I render though the light is not being emitted onto the sphere. I have tried messing with the intensity/exposure, as well as attenuation, to make sure it wasn't just too dim to see. Still nothing.
I have tried using both Ray Tracing and PBR rendering engines and neither work until I uncheck “Ray Variance Anti-aliasing.” With that unchecked though, if I check the “Transform Into This Object” check box it stops emitting light again. If I uncheck the “Transform Into This Object”- check box though it emits light. With “Ray Variance Anti-aliasing” on it does not work whether the “Transform Into This Object” check box is checked or not. So I am wondering if anyone here may have an idea of what might be going on here? Any help or insight you can provide is appreciated. Thanks
I am having an issue in Houdini 15 (latest Build 15.0.347) where the Geo Light is not emitting light when I give it a material. I have found a couple possible problem areas, but still do not understand what the real issue might be that's causing this.
I have it set up so that the Geo Light is using a grid object, as well the same material as that grid (glowing cracks), to emit the light. When I render though the light is not being emitted onto the sphere. I have tried messing with the intensity/exposure, as well as attenuation, to make sure it wasn't just too dim to see. Still nothing.
I have tried using both Ray Tracing and PBR rendering engines and neither work until I uncheck “Ray Variance Anti-aliasing.” With that unchecked though, if I check the “Transform Into This Object” check box it stops emitting light again. If I uncheck the “Transform Into This Object”- check box though it emits light. With “Ray Variance Anti-aliasing” on it does not work whether the “Transform Into This Object” check box is checked or not. So I am wondering if anyone here may have an idea of what might be going on here? Any help or insight you can provide is appreciated. Thanks
Houdini Indie and Apprentice » Change Smoke color according to age/life
- Dustin Tarr
- 12 posts
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Thanks for the reply Mosssi. Yea, I was messing with temperature, but using that I could only get it to gradient from the center out rather than from emission to death/dissipation. I am not sure how to make it more linear, still learning VOP/VEX, but that definitely gives me a direction to look at and something else to google. Thanks!
Houdini Indie and Apprentice » Change Smoke color according to age/life
- Dustin Tarr
- 12 posts
- Offline
Hello,
I am in the midst of really diving deep and learning Houdini. My knowledge is at a beginner knowledge level with dynamics and such but I really enjoy effects and want to learn the ins and outs of Houdini.
Currently, I am working on a personal project/R&D with smoke where I need the color of the smoke to start out one color and change to another over its age. I have messed with the default Temp, Heat, Burn, etc. but it does not give the wanted effect. It needs to be a little more linear. So I thought maybe age would do it, but I do not know enough yet to know how to pipe that into the process and be used by the material. What kind of route can I take to do this? Any help or ideas will be very much appreciated, thank you.
I am in the midst of really diving deep and learning Houdini. My knowledge is at a beginner knowledge level with dynamics and such but I really enjoy effects and want to learn the ins and outs of Houdini.
Currently, I am working on a personal project/R&D with smoke where I need the color of the smoke to start out one color and change to another over its age. I have messed with the default Temp, Heat, Burn, etc. but it does not give the wanted effect. It needs to be a little more linear. So I thought maybe age would do it, but I do not know enough yet to know how to pipe that into the process and be used by the material. What kind of route can I take to do this? Any help or ideas will be very much appreciated, thank you.
Houdini Indie and Apprentice » How to create a continuous Fluid Tank current?
- Dustin Tarr
- 12 posts
- Offline
Enivob
Have you tried adding an Emit Particles object to your setup? If your tank is emptying then you need to fill it. This will create a continuous flow.
Here is an example. After the tanks empties the in flow object keeps particles flowing in the X direction.
That's pretty sweet, Thanks Enivob! That is right down the route I am looking for. Ill rebuild myself just for learning's sake and then tweak to see what I can get out of that. Only question, was there a parameter that allows the particles from the box_in to grab the initial velocity of the tank's or is that just automatic from the source being fed into the flipsolver? Again, pretty cool. Thanks a lot.
Houdini Indie and Apprentice » How to create a continuous Fluid Tank current?
- Dustin Tarr
- 12 posts
- Offline
Hello,
I am just beginning to really dive into Houdini more deeply, as I have only played around with it in the past really. I have been getting into the fluid simulations and dynamics area right now (still very much a beginner in this area), and I have been looking for tutorials on how to set up a fluid tank to have a continuous current. I have not found any unfortunately, only ones on objects moving into and out of a tank. So my question is:
How do I create a Fluid Tank that has a continuous current to move fluid particles past whatever collision geometry is placed within? (for testing like boat wakes, beach waves, etc. for example)
I have set the velocity in initial data to move in the X direction, and to kill particles at the opposite end but that just empties the tank since no particles are being created. It is probably right in front of my face but I have not found the area/node to tell it to birth more particles to create the
continuous flow. What am I missing? Is there a better route?
Thank you in advance to anyone who can help.
I am just beginning to really dive into Houdini more deeply, as I have only played around with it in the past really. I have been getting into the fluid simulations and dynamics area right now (still very much a beginner in this area), and I have been looking for tutorials on how to set up a fluid tank to have a continuous current. I have not found any unfortunately, only ones on objects moving into and out of a tank. So my question is:
How do I create a Fluid Tank that has a continuous current to move fluid particles past whatever collision geometry is placed within? (for testing like boat wakes, beach waves, etc. for example)
I have set the velocity in initial data to move in the X direction, and to kill particles at the opposite end but that just empties the tank since no particles are being created. It is probably right in front of my face but I have not found the area/node to tell it to birth more particles to create the
continuous flow. What am I missing? Is there a better route?
Thank you in advance to anyone who can help.
Houdini Learning Materials » Flip Fluid is evaporating into thin air at simulation time.
- Dustin Tarr
- 12 posts
- Offline
Hey, thanks for replying. I actually came across that just before posting on here. I tried the reseeding route but unfortunately it did not solve the issue. :? If you get a chance to check the work let me know if you find anything. Thanks much though for taking the time to reply.
Houdini Learning Materials » Flip Fluid is evaporating into thin air at simulation time.
- Dustin Tarr
- 12 posts
- Offline
Hi,
I am a novice at Houdini 14 and just getting into particles and fluids. I am creating a tea pot pouring into a cup and had it working for a while but the pour animation caused it to fly out of the spout too much. When I adjusted the animation of the teapot to fix that, my fluids now begin to collapse into thin air within around 15 frames or so and I am left with almost no particles. I have tweaked all kinds of parameters in trying to hunt down the culprit of this to no avail. There is an fbx I imported to houdini but unfortunately it will not let me attach it so I hope you can maybe still see the parameters that are set. I have attached screenshots to at least show what is happeining. (I turned off the teapot geometry so that you can more clearly see what is happening.) Any help would be much appreciated.
I am a novice at Houdini 14 and just getting into particles and fluids. I am creating a tea pot pouring into a cup and had it working for a while but the pour animation caused it to fly out of the spout too much. When I adjusted the animation of the teapot to fix that, my fluids now begin to collapse into thin air within around 15 frames or so and I am left with almost no particles. I have tweaked all kinds of parameters in trying to hunt down the culprit of this to no avail. There is an fbx I imported to houdini but unfortunately it will not let me attach it so I hope you can maybe still see the parameters that are set. I have attached screenshots to at least show what is happeining. (I turned off the teapot geometry so that you can more clearly see what is happening.) Any help would be much appreciated.
Edited by - Feb. 15, 2015 19:59:52
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