I'm struggling with the same issue here.
Is this a (confirmed) bug or by design? Especially since this worked in older versions.
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Technical Discussion » No collision between Cloth and Solid object
- schyzomaniac
- 69 posts
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Technical Discussion » How to set initial state for certain dynamic objects?
- schyzomaniac
- 69 posts
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Hi all
I stumbled across a problem and need help. ops:
I played around a little bit with dynamics and fluids and wanted to settle my fluid sim before I'd continue doing other stuff with it.
So after my fluid settled down, I used a file node to write out that frame as a .sim and used it as the initial state inside the AutoDopNetwork node.
When I go back to frame 1, everything seems fine. The state of the fluids is where I need them.
But when I now try to introduce a rigid body object (sphere) to my Dop network, it gets ignored (invisible).
I guess it's because when I wrote out the .sim file, it wasn't included at that time. So now, on the initial frame the DOP network is not aware of that sphere.
When I dive into the sphere node, I see a warning on the dopimport1 node. It says “No DOP object names specified”.
What does that mean? How can I fix it?
Since I'm not sure where I want to go with the sim, it's impossible for me to foresee all possible RDB objects that I might need in the future. This is purely for testing purposes. But I need to somehow safe an initial state of my water before I can continue.
Any advice, tips?
cheers,
Daniel
I stumbled across a problem and need help. ops:
I played around a little bit with dynamics and fluids and wanted to settle my fluid sim before I'd continue doing other stuff with it.
So after my fluid settled down, I used a file node to write out that frame as a .sim and used it as the initial state inside the AutoDopNetwork node.
When I go back to frame 1, everything seems fine. The state of the fluids is where I need them.
But when I now try to introduce a rigid body object (sphere) to my Dop network, it gets ignored (invisible).
I guess it's because when I wrote out the .sim file, it wasn't included at that time. So now, on the initial frame the DOP network is not aware of that sphere.
When I dive into the sphere node, I see a warning on the dopimport1 node. It says “No DOP object names specified”.
What does that mean? How can I fix it?
Since I'm not sure where I want to go with the sim, it's impossible for me to foresee all possible RDB objects that I might need in the future. This is purely for testing purposes. But I need to somehow safe an initial state of my water before I can continue.
Any advice, tips?
cheers,
Daniel
Technical Discussion » weird fluid volume behavior
- schyzomaniac
- 69 posts
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alejandro, thanks a lot for your suggestions and tips.
Sorry for replying so late, but I just had time to try the things you mentioned out.
While they definitely help to improve the simulation, I somehow remember this was easier a couple of versions ago. And with easier I mean the result would have been more predictable without tweaking so many parameters. Only decreasing the voxel size would already to help to get a better result.
But maybe I remember things wrong - who knows?
cheers,
Daniel
Sorry for replying so late, but I just had time to try the things you mentioned out.
While they definitely help to improve the simulation, I somehow remember this was easier a couple of versions ago. And with easier I mean the result would have been more predictable without tweaking so many parameters. Only decreasing the voxel size would already to help to get a better result.
But maybe I remember things wrong - who knows?
cheers,
Daniel
Technical Discussion » weird fluid volume behavior
- schyzomaniac
- 69 posts
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hcmistryvfx, could you check if your point count is increasing or changing at all during simulation?
Mine is increasing steadily.
Mine is increasing steadily.
hcmistryvfx
I opened up file and tested and everything seems to be right.
I am not getting more fluid in my container.
Something might be wrong with Houdini Version so just try with different version.
I am using 12.5.375
Technical Discussion » weird fluid volume behavior
- schyzomaniac
- 69 posts
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Skybar, I can only find the reseeding option on the FLIP solver, but not the fluid solver - which I am using here.
Is there a similar parameter that does the same but is named differently?
This is starting to drive me crazy. Can't even do the most simple simulation.
Is no body else experiencing those issues?
Is there a similar parameter that does the same but is named differently?
This is starting to drive me crazy. Can't even do the most simple simulation.
Is no body else experiencing those issues?
Technical Discussion » weird fluid volume behavior
- schyzomaniac
- 69 posts
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I downloaded two new builds (latest production and daily), but I still get this behavior.
hcmistryvfx, if you don't mind, could you re-save my file with your Houdini version and send it back?
Or just add a screenshot of your last simulated frame? I am curious how it looks on your end.
I tried using shelf tools as well as manually building the node network. But I always end up with the same issue that the fluid is “growing”.
Triple checked all parameters, but running out of ideas.
cheers,
Daniel
hcmistryvfx, if you don't mind, could you re-save my file with your Houdini version and send it back?
Or just add a screenshot of your last simulated frame? I am curious how it looks on your end.
I tried using shelf tools as well as manually building the node network. But I always end up with the same issue that the fluid is “growing”.
Triple checked all parameters, but running out of ideas.
cheers,
Daniel
Technical Discussion » weird fluid volume behavior
- schyzomaniac
- 69 posts
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Hi everyone
I was just running some basic fluid tests, when I run into this problem.
Basically I just created a fluid container, a sphere and then made the sphere a liquid object.
So the sphere is emitting a single volume of liquid, as expected and hits the bottom of the liquid container.
After that I get some splashes - also as expected - and some “interesting” behavior. It seems like the amount of liquid is increasing.
After the fluid settles down I have much more liquid volume than the initial emitter (sphere).
Another issue is that when I increase the amount of sub steps, I get even more liquid volume.
Attached are two videos and the hip file to illustrate the problem. Maybe someone can tell me what I am doing wrong here.
Thanks,
Daniel
I was just running some basic fluid tests, when I run into this problem.
Basically I just created a fluid container, a sphere and then made the sphere a liquid object.
So the sphere is emitting a single volume of liquid, as expected and hits the bottom of the liquid container.
After that I get some splashes - also as expected - and some “interesting” behavior. It seems like the amount of liquid is increasing.
After the fluid settles down I have much more liquid volume than the initial emitter (sphere).
Another issue is that when I increase the amount of sub steps, I get even more liquid volume.
Attached are two videos and the hip file to illustrate the problem. Maybe someone can tell me what I am doing wrong here.
Thanks,
Daniel
Technical Discussion » Bug? Refraction/Reflection ignores Light linking in PBR
- schyzomaniac
- 69 posts
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Technical Discussion » Bug? Refraction/Reflection ignores Light linking in PBR
- schyzomaniac
- 69 posts
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Bump.
No one? Is this a common problem? Should I issue a bug report?
Can I issue a bug report as an apprentice user?
cheers,
Daniel
No one? Is this a common problem? Should I issue a bug report?
Can I issue a bug report as an apprentice user?
cheers,
Daniel
Houdini Indie and Apprentice » GlasMat with Fresnel Alpha?
- schyzomaniac
- 69 posts
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Hi
I am encountering the same issue at the moment, where I would need black (or shades or grey) in the alpha whenever a ray doesn't hit anything.
Right now I am getting solid white everywhere I have refractions.
This is okay for most of the time when working with backplates. But sometimes I need to put glass-like objects on a background later in comp, and therefore need transparency.
I tried the luminance VOP that Jeff suggested, but it just takes the average of the luminance from C and pipes it into AF, therefore ignoring if the ray continues and hits a solid pixel “behind” a refractive pixel. This introduces transparency where it's not supposed to be.
Any other advises then the ones mentioned above?
cheers,
Daniel
I am encountering the same issue at the moment, where I would need black (or shades or grey) in the alpha whenever a ray doesn't hit anything.
Right now I am getting solid white everywhere I have refractions.
This is okay for most of the time when working with backplates. But sometimes I need to put glass-like objects on a background later in comp, and therefore need transparency.
I tried the luminance VOP that Jeff suggested, but it just takes the average of the luminance from C and pipes it into AF, therefore ignoring if the ray continues and hits a solid pixel “behind” a refractive pixel. This introduces transparency where it's not supposed to be.
Any other advises then the ones mentioned above?
cheers,
Daniel
Technical Discussion » Bug? Refraction/Reflection ignores Light linking in PBR
- schyzomaniac
- 69 posts
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Hi
I am not sure if I encountered a bug, or if this is by design. In any case it's not correct and I would like to know if there is a solution for this.
Attached you'll see a screenshot* of a very simple scene setup. A floor, a glass torus and one area light.
In the light linker I disconnected the floor from the area light, therefore receiving no illumination in the scene.
But in the glass torus refraction/reflection the floor is still being illuminated by the area light.
I am using PBR with mostly default settings.
Does anybody know a workaround/solution for this, so that refractions respect light linking?
cheers,
Daniel
* top image shows scene without light linking, and bottom image shows floor being disconnected from the area light.
//edit:
apparently this doesn't happen when using Micropolygon or Raytracing. Only when using Micropolygon PBR or PBR.
I am not sure if I encountered a bug, or if this is by design. In any case it's not correct and I would like to know if there is a solution for this.
Attached you'll see a screenshot* of a very simple scene setup. A floor, a glass torus and one area light.
In the light linker I disconnected the floor from the area light, therefore receiving no illumination in the scene.
But in the glass torus refraction/reflection the floor is still being illuminated by the area light.
I am using PBR with mostly default settings.
Does anybody know a workaround/solution for this, so that refractions respect light linking?
cheers,
Daniel
* top image shows scene without light linking, and bottom image shows floor being disconnected from the area light.
//edit:
apparently this doesn't happen when using Micropolygon or Raytracing. Only when using Micropolygon PBR or PBR.
Technical Discussion » Luminous Surface not emitting light through glass
- schyzomaniac
- 69 posts
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Technical Discussion » Luminous Surface not emitting light through glass
- schyzomaniac
- 69 posts
- Offline
Hi
I made a simple test with some liquid inside a torus shape. I extruded the torus just so slightly, so that it has a little bit of thickness and add a glass shader.
For the liquid I use a standard mantra surface shader with “Emission” turned on.
The problem I have right now is that the liquid is not illuminating the floor beneath it. When I hide the glass torus or set the opacity in the glass shader to 0, the floor gets illuminated. But of course that's not what I need. The emitted light should travel through the glass shader.
Is there a way to either modify the glass shader, so that the illumination from the liquid passes through, or is there a setting in either the shader or render option that might help in this kind of scenario?
cheers,
Daniel
I made a simple test with some liquid inside a torus shape. I extruded the torus just so slightly, so that it has a little bit of thickness and add a glass shader.
For the liquid I use a standard mantra surface shader with “Emission” turned on.
The problem I have right now is that the liquid is not illuminating the floor beneath it. When I hide the glass torus or set the opacity in the glass shader to 0, the floor gets illuminated. But of course that's not what I need. The emitted light should travel through the glass shader.
Is there a way to either modify the glass shader, so that the illumination from the liquid passes through, or is there a setting in either the shader or render option that might help in this kind of scenario?
cheers,
Daniel
Houdini Lounge » Question about the Mantra Surface material
- schyzomaniac
- 69 posts
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johm
if you're dead set against using an expression to make an inverse relationship between diffuse color and reflected color, you could always modify the shader network to make it “automatic”.
Not at all. I am happy to plug in an expression. Just want to make sure it's the correct one.
So diffuse should always be 1 - reflectivity?
And penboak, thanks for the documentation tip. I will certainly read up on this.
Daniel
Houdini Lounge » Question about the Mantra Surface material
- schyzomaniac
- 69 posts
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Thank you for your reply penboak.
Actually, I am quiet aware of the differences between specularity, reflection and how sometimes I use one word to describe the other. Maybe my initial post was a bit confusing because of that.
What I am looking for is a description of diffuse, when ever I use specularity/reflection.
Again, if I have a red diffuse color, but then pump up the reflectivity to 100%, shouldn't this completely override the diffuse color? If an object is 100% reflective, all I should see are the reflections, right?
But with the Mantra Surface Shader, I need to control this manually. So the question would be, that whenever I use a reflectivity value higher than zero, what is the appropriate value for diffuse?
Is it something like
diffuse = 1 - reflectivity? Or is it more complex than that?
Hope that makes my question/confusion a bit clearer.
cheers,
Daniel
Actually, I am quiet aware of the differences between specularity, reflection and how sometimes I use one word to describe the other. Maybe my initial post was a bit confusing because of that.
What I am looking for is a description of diffuse, when ever I use specularity/reflection.
Again, if I have a red diffuse color, but then pump up the reflectivity to 100%, shouldn't this completely override the diffuse color? If an object is 100% reflective, all I should see are the reflections, right?
But with the Mantra Surface Shader, I need to control this manually. So the question would be, that whenever I use a reflectivity value higher than zero, what is the appropriate value for diffuse?
Is it something like
diffuse = 1 - reflectivity? Or is it more complex than that?
Hope that makes my question/confusion a bit clearer.
cheers,
Daniel
Houdini Lounge » Question about the Mantra Surface material
- schyzomaniac
- 69 posts
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Hi
I have a general question about how to use the Mantra Surface material.
Having a strong mental ray/mia_material background, I like to work as physical plausible as possible.
If I have a specular intensity value of 1, I would assume that this results in a 100% reflective object (if fresnel blending is disabled). But this is only true if my diffuse value is set to 0 or is disabled (unlike in MR).
Now, in that case one could argue that it's kind of logical to put diffuse to zero if you're aiming for a 100% reflective surface.
But what if my reflectivity should be 75%? Do I need to set diffuse to 25% then? What is the correct math for this?
Is it as simple as 1 - specular = diffuse?
And shouldn't reflectivity always “overwrite” diffuse? When I set reflectivity/specular to 1, how come I can still see it's getting added to the diffuse color? It doesn't make much sense to me if it's set to 1.
Or maybe my logic is broken somewhere?
Could someone guide me to a place where I can read more about this? How to balance diffuse, specular and refraction “against” each other?
cheers,
Daniel
On a side node - Is it possible to give the coat reflection a different IOR than the base reflection?
I have a general question about how to use the Mantra Surface material.
Having a strong mental ray/mia_material background, I like to work as physical plausible as possible.
If I have a specular intensity value of 1, I would assume that this results in a 100% reflective object (if fresnel blending is disabled). But this is only true if my diffuse value is set to 0 or is disabled (unlike in MR).
Now, in that case one could argue that it's kind of logical to put diffuse to zero if you're aiming for a 100% reflective surface.
But what if my reflectivity should be 75%? Do I need to set diffuse to 25% then? What is the correct math for this?
Is it as simple as 1 - specular = diffuse?
And shouldn't reflectivity always “overwrite” diffuse? When I set reflectivity/specular to 1, how come I can still see it's getting added to the diffuse color? It doesn't make much sense to me if it's set to 1.
Or maybe my logic is broken somewhere?
Could someone guide me to a place where I can read more about this? How to balance diffuse, specular and refraction “against” each other?
cheers,
Daniel
On a side node - Is it possible to give the coat reflection a different IOR than the base reflection?
Technical Discussion » Initial Veloctiy not working with particle fluid objects
- schyzomaniac
- 69 posts
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Hello Jeff
Thank you so much for answering my questions in such detail. I really appreciate it. And since you did such a great job telling me what I did wrong or missed, everything works fine now and I can continue to dive into the FLIP fluid solver.
Next I will definetly watch the masterclass.
Thanks again,
Daniel
Thank you so much for answering my questions in such detail. I really appreciate it. And since you did such a great job telling me what I did wrong or missed, everything works fine now and I can continue to dive into the FLIP fluid solver.
Next I will definetly watch the masterclass.
Thanks again,
Daniel
Technical Discussion » Initial Veloctiy not working with particle fluid objects
- schyzomaniac
- 69 posts
- Offline
Hi
I was trying to play around with FLIP fluids, but after five minutes I already run into my first problem, which I cannot solve by myself.
I created a sphere, moved it up and rotated it slightly, so that it's local Y-axis is pointing 45° to the right. I then converted it into a “Emit Particle fluids”, by using the shelf tools. When asked I chose Flip fluids (but it also didn't work with SPH).
In the AutoDOP network, in the particleFluidObject1 node, under the Initial Data Tab, I tried to modify the direction the fluids get emitted. But no matter what I enter into x, y and z, the fluids always come out the same way.
As my Input type I used the default “Surface SOP”. In the manual it says “…Use this option to generate particles inside of the specified surface…”.
But in my scene only at the point positions particles get generated, not from the volume.
So my questions are:
- How can I control the initial direction in which fluids get emitted?
- How can I emit FLIP fluids from a volume instead point positions?
cheers,
Daniel
p.s. A bonus question to avoid multiple threads
- Why are Viscosity and Surface Tension disabled in the FLIP fluids?
I was trying to play around with FLIP fluids, but after five minutes I already run into my first problem, which I cannot solve by myself.
I created a sphere, moved it up and rotated it slightly, so that it's local Y-axis is pointing 45° to the right. I then converted it into a “Emit Particle fluids”, by using the shelf tools. When asked I chose Flip fluids (but it also didn't work with SPH).
In the AutoDOP network, in the particleFluidObject1 node, under the Initial Data Tab, I tried to modify the direction the fluids get emitted. But no matter what I enter into x, y and z, the fluids always come out the same way.
As my Input type I used the default “Surface SOP”. In the manual it says “…Use this option to generate particles inside of the specified surface…”.
But in my scene only at the point positions particles get generated, not from the volume.
So my questions are:
- How can I control the initial direction in which fluids get emitted?
- How can I emit FLIP fluids from a volume instead point positions?
cheers,
Daniel
p.s. A bonus question to avoid multiple threads
- Why are Viscosity and Surface Tension disabled in the FLIP fluids?
Houdini Lounge » Fixing slow selection problem with ATI cards
- schyzomaniac
- 69 posts
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Hey. That seems to work fine. Where did you get the lucky numbes from? Which profile?
I'm having a HD2600 Radeaon in my laptop by the way. Never ever ATI again after this one. I don't know how they can screw up their drivers so badly.
Anyway - enough ranting.
Thanks for the tip! It seems to work now.
Daniel
I'm having a HD2600 Radeaon in my laptop by the way. Never ever ATI again after this one. I don't know how they can screw up their drivers so badly.
Anyway - enough ranting.
Thanks for the tip! It seems to work now.
Daniel
Houdini Lounge » Fixing slow selection problem with ATI cards
- schyzomaniac
- 69 posts
- Offline
Selection works fine with this trick. Unfortunately I can't move objects properly in their z-axis anymore when changing the xml file.
Anyone else with this problem?
Daniel
Anyone else with this problem?
Daniel
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