Also note that if you want to vary the density per particles, what I usually do is create an Alpha parameter on the shader, promote it to the material level so I can use the override mechanism. Then I multiply the incoming density attribute directly by that Alpha parameter in the shader.
François
P.S.: I'd love to understand why the render can be very long when the scaling of each puff is too large. Could it be made faster by increasing the puff resolution to an insanely high amount.
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Houdini Lounge » Volume instancing with overrides
- francoisd
- 137 posts
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Houdini Lounge » Volume instancing with overrides
- francoisd
- 137 posts
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After a discussion on the mailing list, here's a hip file to demonstrate how to do volume instancing with overrides per instance.
Here are the main lines
-A Material Sop set to “Point Attribute” has to be put in the Instance OBJ
-You must select what parameter you want to override on the shader and set the values from any attribute that exists on the sop.
-Create a Geometry OBJ with a small volume in it. Don't attach any shader to it.
The only downside I've found is that the python generation can be a little bit long when there are many particles.
Also, it's better to have a high res volume to save time at rendering. It looks like the renderer has less interpolation to do when it can query the value of a voxel directly. Anyone has a better explanation for that?
François
Here are the main lines
-A Material Sop set to “Point Attribute” has to be put in the Instance OBJ
-You must select what parameter you want to override on the shader and set the values from any attribute that exists on the sop.
-Create a Geometry OBJ with a small volume in it. Don't attach any shader to it.
The only downside I've found is that the python generation can be a little bit long when there are many particles.
Also, it's better to have a high res volume to save time at rendering. It looks like the renderer has less interpolation to do when it can query the value of a voxel directly. Anyone has a better explanation for that?
François
Technical Discussion » camera projection distortion
- francoisd
- 137 posts
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Sorry for bringing back an old discussion but this caused me lots of headaches and I thought others might like to get the info.
For rendering we must use a shader that convert the P rest world space to NDC but even with this method it still has some artifact if the geometry is not very uniformly divided.
What I had to do to make it work is to force the “Rendering Engine” menu to “Raytracing” on the Mantra Rop.
François
For rendering we must use a shader that convert the P rest world space to NDC but even with this method it still has some artifact if the geometry is not very uniformly divided.
What I had to do to make it work is to force the “Rendering Engine” menu to “Raytracing” on the Mantra Rop.
François
Technical Discussion » [BUG] the paint and sculpt sop does not work in win 32bit
- francoisd
- 137 posts
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Oh, I forgot this thread. I posted more info on this one.
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=74223#74223 [sidefx.com]
Today SideFx told me it is fixed on 10.0.271.
François
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=74223#74223 [sidefx.com]
Today SideFx told me it is fixed on 10.0.271.
François
Houdini Indie and Apprentice » Sculpt tool doesn't work
- francoisd
- 137 posts
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I've managed to find how to recreate the bug and I actually have a workaround. I've posted the bug at SideFX.
The problem arises when you right click with your stylus on the brush tool to get the menu. If you don't click on an item in the menu and leave back to the viewer, the brush will stop working.
In order to make it work again, right-click again and chose whatever option in the brush menu and it should be fine.
Let me know if it doesn't work but I've been able to repeat that behavior 10 times in a row.
François
The problem arises when you right click with your stylus on the brush tool to get the menu. If you don't click on an item in the menu and leave back to the viewer, the brush will stop working.
In order to make it work again, right-click again and chose whatever option in the brush menu and it should be fine.
Let me know if it doesn't work but I've been able to repeat that behavior 10 times in a row.
François
Technical Discussion » [BUG] the paint and sculpt sop does not work in win 32bit
- francoisd
- 137 posts
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Do you guys still have that issues? I want to report the bug to SideFx but I can't produce the bug on demand.
The link Dragos put doesn't work but if you know how to repeat it on demand I'd like to know it. Also if there's an other work around then restarting Houdini I'd love to know how.
François
The link Dragos put doesn't work but if you know how to repeat it on demand I'd like to know it. Also if there's an other work around then restarting Houdini I'd love to know how.
François
Technical Discussion » Particle fluids without stream emission
- francoisd
- 137 posts
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Hi Steven,
I tried what you said but it doesn't work with my rest density * 0.9. Instead I had to write directly 0.2 without the multiplication. I think they've changed the way this parameter works because in the help they say they internally multiply it by the rest density.
However with 0.2 it still behaves differently when the first particles hit the ground. With stream emission I don't feel any change in the flow.
The other thing I like with stream emission is the speed. It looks like it generates let's say 3 rows in 1 timestep if it needs to fit with the speed which is great.
I guess now my question should be, how can I use the stream emission with a different direction per point based on the normal maybe.
That would be also great to be able to do that in Pop too to avoid oversampling too much just to have a nice distribution.
If it's not possible I would make a RFE. What do you think about that?
François
I tried what you said but it doesn't work with my rest density * 0.9. Instead I had to write directly 0.2 without the multiplication. I think they've changed the way this parameter works because in the help they say they internally multiply it by the rest density.
However with 0.2 it still behaves differently when the first particles hit the ground. With stream emission I don't feel any change in the flow.
The other thing I like with stream emission is the speed. It looks like it generates let's say 3 rows in 1 timestep if it needs to fit with the speed which is great.
I guess now my question should be, how can I use the stream emission with a different direction per point based on the normal maybe.
That would be also great to be able to do that in Pop too to avoid oversampling too much just to have a nice distribution.
If it's not possible I would make a RFE. What do you think about that?
François
Technical Discussion » Particle fluids without stream emission
- francoisd
- 137 posts
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Is it possible to emit particle fluids without the “Use Stream Emission”
and have a good result.
My first try is to set my birth rate per impulse. The problem with that
is as soon as a collision occurs, my emission become unstable. I think
what is happening is that the number of sub-step is calculated
automatically and it needs more sub-step with a collision and then a lot
more particles are born at this time.
The other solution is with constant birth rate but I cannot have a nice
distribution of all the points at the same time. For example, half of
them are created on a different sub-step then the rest.
Any ideas? I tried this question on the mailing without sucess.
Thanks
François
and have a good result.
My first try is to set my birth rate per impulse. The problem with that
is as soon as a collision occurs, my emission become unstable. I think
what is happening is that the number of sub-step is calculated
automatically and it needs more sub-step with a collision and then a lot
more particles are born at this time.
The other solution is with constant birth rate but I cannot have a nice
distribution of all the points at the same time. For example, half of
them are created on a different sub-step then the rest.
Any ideas? I tried this question on the mailing without sucess.
Thanks
François
Houdini Lounge » pop attractor not working as expected
- francoisd
- 137 posts
- Offline
I think what you're looking for is the Follow Pop. I've included an example file.
François
François
Technical Discussion » Houdini on 64 bit Linux, any advice?
- francoisd
- 137 posts
- Offline
Thanks guys. It's working now since I've installed my nVidia drivers.
I'm still interested to know the performance difference between 32 and 64-bit in the case I have some drivers issues and I hesitate to come back to 32-bit.
François
I'm still interested to know the performance difference between 32 and 64-bit in the case I have some drivers issues and I hesitate to come back to 32-bit.
François
Technical Discussion » Houdini on 64 bit Linux, any advice?
- francoisd
- 137 posts
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I will install my video card drivers before trying to run Houdini. I didn't know it was for that reason because on a 32-bit Linux I can run Houdini directly without those drivers.
By the way, is it a notable performance difference between 32-Bit and 64-Bit Linux in Houdini. Where I would expect a gain is while running fluid simulation for example.
Thanks
François
By the way, is it a notable performance difference between 32-Bit and 64-Bit Linux in Houdini. Where I would expect a gain is while running fluid simulation for example.
Thanks
François
Technical Discussion » Houdini on 64 bit Linux, any advice?
- francoisd
- 137 posts
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I answered too fast your question. It was easier for me to install Suse than the other distros in 32 bit but with 64 bit I'm not able to run it with Open Suse 10.2 64 bit.
The error I got is: “Segmentation fault” when lauching Houdini. I use the 64 bit version. So I'll ask the same question as Edward to J.C.
François
The error I got is: “Segmentation fault” when lauching Houdini. I use the 64 bit version. So I'll ask the same question as Edward to J.C.
François
Technical Discussion » Houdini on 64 bit Linux, any advice?
- francoisd
- 137 posts
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I don't have much experience with Linux but I've tried Ubuntu, Debian and Gentoo but the one that was the easiest was Suse. I recomand it as a starting point.
Technical Discussion » need good pdfs or books for houdini
- francoisd
- 137 posts
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I'm not sure I understand your question but if do then what I strongly suggest is always start with the fondations.
In this case the Craig Zerouni book is better when you already know the software for several weeks and want to get tricks to be more productive.
On the other hand “The magic of Houdini” IS the foundation.
In this case the Craig Zerouni book is better when you already know the software for several weeks and want to get tricks to be more productive.
On the other hand “The magic of Houdini” IS the foundation.
Technical Discussion » need good pdfs or books for houdini
- francoisd
- 137 posts
- Offline
Thanks Alex
I've added the video tutorials section in the OdForce wiki here
http://odforce.net/wiki/index.php/ExternalHoudiniResources#Education [odforce.net]
I'm sure more can be added.
I've also created the “Learning DVDs” page.
Ciao!
I've added the video tutorials section in the OdForce wiki here
http://odforce.net/wiki/index.php/ExternalHoudiniResources#Education [odforce.net]
I'm sure more can be added.
I've also created the “Learning DVDs” page.
Ciao!
Technical Discussion » need good pdfs or books for houdini
- francoisd
- 137 posts
- Offline
I've bought the following under the “Learning material” section. Here are my comments.
The book “The magic of Houdini” is definitly the right place to start if you plan to seriously learn Houdini. It's longer than watching at some video tutorials but you'll cover a great amount of features.
“Rigid body dynamics DVD” is worth buying it if want to do FX.
“Houdini L-Systems Essentials 1” is a good DVD. I'll buy the second one when I finish the first but it's not something you should start with. Actually, this is a rather advanced feature in Houdini.
Here are other links with video tutorials but I still advise you to start with the book to cover the basis.
http://www.cmivfx.com/tutorials.asp [cmivfx.com]
http://www.miguelperezsenent.com/ [miguelperezsenent.com]
Hey SESI, what about a wiki section or something in this web site where anyone could post all the learning links found all around the world.
Good luck!
The book “The magic of Houdini” is definitly the right place to start if you plan to seriously learn Houdini. It's longer than watching at some video tutorials but you'll cover a great amount of features.
“Rigid body dynamics DVD” is worth buying it if want to do FX.
“Houdini L-Systems Essentials 1” is a good DVD. I'll buy the second one when I finish the first but it's not something you should start with. Actually, this is a rather advanced feature in Houdini.
Here are other links with video tutorials but I still advise you to start with the book to cover the basis.
http://www.cmivfx.com/tutorials.asp [cmivfx.com]
http://www.miguelperezsenent.com/ [miguelperezsenent.com]
Hey SESI, what about a wiki section or something in this web site where anyone could post all the learning links found all around the world.
Good luck!
Technical Discussion » howto: German Keyboards and {[]}|
- francoisd
- 137 posts
- Offline
I have the same issue with a french keyboard (French Canadian). Since Houdini will become more and more used all around the world that would be great if SESI fix it.
François
P.S.: I must admit I prefer having the new fluid system in H9 and keep switching my keyboard
François
P.S.: I must admit I prefer having the new fluid system in H9 and keep switching my keyboard
Technical Discussion » howto: German Keyboards and {[]}|
- francoisd
- 137 posts
- Offline
I have the same issue with a french keyboard (French Canadian). Since Houdini will become more and more used all around the world that would be great if SESI fix it.
François
P.S.: I must admit I prefer having the new fluid system in H9 and keep switching my keyboard
François
P.S.: I must admit I prefer having the new fluid system in H9 and keep switching my keyboard
Houdini Lounge » Houdini internship in Toronto
- francoisd
- 137 posts
- Offline
Hi, I have some spare time this summer from 13 to 24 of august and I would like to do a free Houdini internship in a Toronto company. I know it's not very long but unfortunatly this is all the time I can give.
You can see my FX demos on www.trinix.ca under “Demo”. For more details on me check my cv under “Contact”.
Thanks!
François
You can see my FX demos on www.trinix.ca under “Demo”. For more details on me check my cv under “Contact”.
Thanks!
François
Technical Discussion » Ecosystem simulation....and vex question...
- francoisd
- 137 posts
- Offline
I've played around with L-System a bit but unfortunatly I haven't gone far enough to help you.
On the other hand I've ordered the L-System DVD #1 from CMI VFX and I will order the second one if I like the first. I've read somewhere they plan to release 4 of them in total. Each of them is 4 hours so I guess you can find very valuable information.
I can let you know when I receive it to tell you if it's good but you can ask them if what you're looking for is covered in it.
http://www.cmivfx.com/product_houdini_lsystems1.asp [cmivfx.com]
François
On the other hand I've ordered the L-System DVD #1 from CMI VFX and I will order the second one if I like the first. I've read somewhere they plan to release 4 of them in total. Each of them is 4 hours so I guess you can find very valuable information.
I can let you know when I receive it to tell you if it's good but you can ask them if what you're looking for is covered in it.
http://www.cmivfx.com/product_houdini_lsystems1.asp [cmivfx.com]
François
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