I am trying to simulate a simple wind tunnel test with a continuous wind flow inside a constant volume with one static building object as collision.
I have run it for 240 frames, I find that the length and angle of velocity vector constantly keeps changing through out the volume.
How do we determine when to stop the simulation? Is there a way we can let the simulation settle and converge to a point beyond which there is minimal change in velocity vector?
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Technical Discussion » when to stop a smoke simulation?
- vigneshkaushik
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Technical Discussion » Velocity sampling in smoke solver
- vigneshkaushik
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On the Smoke object in the dynamics network, inisde the Initial data tab, the default for Velocity sampling is “Faces”. I understand that despite being slower, this gives more accurate collisions of smoke with another dynamic object.
I would like to know whether it is the same for static objects like buildings also. If not can we set velocity sampling to “Centers” for a faster simulation?
I would like to know whether it is the same for static objects like buildings also. If not can we set velocity sampling to “Centers” for a faster simulation?
Technical Discussion » Algorithm used for smoke
- vigneshkaushik
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These are links to some papers I found online about Houdini's smoke and fluid solvers. They seem to suggest that the incompressible Navier-Stokes equation is used as the base for most of these solvers with tweaks here and there to improve realism, speed and computational power. Also there seems to be three main methods used in Houdini; Smooth Particle Hydrodynamics (SPH), Volume Grid approaches based on voxels and FLIP which is a type of hybrid between a particle based and volume based fluid simulations.
http://www.cescg.org/CESCG-2007/papers/TUBudapest-Horvath-Peter/TUBudapest-Horvath-Peter.pdf [cescg.org]
http://www.peterclaes.be/tutorials/pct_0007.pdf [peterclaes.be]
http://www.fxguide.com/featured/the-science-of-fluid-sims/ [fxguide.com]
Has anyone compared the results of these simulations with a more academic CFD software package like Fluent, ScStream etc?
http://www.cescg.org/CESCG-2007/papers/TUBudapest-Horvath-Peter/TUBudapest-Horvath-Peter.pdf [cescg.org]
http://www.peterclaes.be/tutorials/pct_0007.pdf [peterclaes.be]
http://www.fxguide.com/featured/the-science-of-fluid-sims/ [fxguide.com]
Has anyone compared the results of these simulations with a more academic CFD software package like Fluent, ScStream etc?
Technical Discussion » Wind profile
- vigneshkaushik
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Does changing the border type from constant to repeat help? I have attached screenshot of both scenarios. In border type=repeat, the volume seems to wrap returning values from opposite side of the volume. I am not entirely sure if that is the same as a constant initial wind profile. Can someone clarify pls?
Technical Discussion » Smoke DOP variable initial velocity
- vigneshkaushik
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I am trying to create a wind tunnel simulation using smoke DOP and would like to have a variable initial velocity (say, varying along height, the higher it is more the velocity) instead of fixed x,y,z velocity.
How to do this?
Thanks for your help.
How to do this?
Thanks for your help.
Work in Progress » CFD in Houdini
- vigneshkaushik
- 20 posts
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Thanks a lot Jeff. Thats fantastic. I have been exploring smoke and pyro DOPs for the past few days but got nothing quite as close to what you have shown. I will have a look at the file attached and will post further questions which I may have.
Work in Progress » CFD in Houdini
- vigneshkaushik
- 20 posts
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Hi heydabop,
I know its been 5 years since, but would you pls share your .hip files if you still have them. It would be very useful to understand how it is done. Thanks.
I know its been 5 years since, but would you pls share your .hip files if you still have them. It would be very useful to understand how it is done. Thanks.
Houdini Indie and Apprentice » Unable to export .obj/.dxf files
- vigneshkaushik
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Houdini Indie and Apprentice » unable to read .obj file
- vigneshkaushik
- 20 posts
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Hello All,
Unfortunately I am facing the same issue with Houdini 13.0.509. I was able to read/write .obj and .dxf files just a week ago and since then unable to do so.
I am not sure what changed in the last one week. I tried deleting the entire Houdini preferences folder in $HOME directory and still the problem persists. I also checked the environment variables for $HFS/bin and they seem to be alrite.
Where am I going wrong? What am I missing? I really need to get this sorted out for my workflow.
Thanks a bunch for your suggestions.
Unfortunately I am facing the same issue with Houdini 13.0.509. I was able to read/write .obj and .dxf files just a week ago and since then unable to do so.
I am not sure what changed in the last one week. I tried deleting the entire Houdini preferences folder in $HOME directory and still the problem persists. I also checked the environment variables for $HFS/bin and they seem to be alrite.
Where am I going wrong? What am I missing? I really need to get this sorted out for my workflow.
Thanks a bunch for your suggestions.
Houdini Indie and Apprentice » Unable to export .obj/.dxf files
- vigneshkaushik
- 20 posts
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Hey All,
I am facing problems with reading/writing formats other than .bgeo. I use the file SOP to import/export to .obj or .dxf files and I get a file with no data(0 kb files). I use Houdini 13.0.509 and have successfully read/write .obj and .dxf using this same version before.
I cannot understand what has changed that suddenly wouldnt allow me to read/write other geometry formats. I need your help. Thanks.
I am facing problems with reading/writing formats other than .bgeo. I use the file SOP to import/export to .obj or .dxf files and I get a file with no data(0 kb files). I use Houdini 13.0.509 and have successfully read/write .obj and .dxf using this same version before.
I cannot understand what has changed that suddenly wouldnt allow me to read/write other geometry formats. I need your help. Thanks.
Houdini Lounge » toon rendering
- vigneshkaushik
- 20 posts
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edwardPP789
In fact I've don't really understand why they create 2 file format. I don't really see the difference between both.
.hipnc is the NON-commercial file format while .hip is the commercial file format. Loading a non-commercial .hipnc will always cause your Houdini session to go into non-commercial mode (with watermarked panes, non-commercial limitations, etc). Basically, it just means that everything will work with loading except that you can't convert non-commercial files into commercial ones.
but how come WREN doesnt work for me in the non-commercial edition?? and is there any other good shaders for architectural renderings??
Houdini Indie and Apprentice » unique selection of primitives
- vigneshkaushik
- 20 posts
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thanks a lot for your input. however, this is not exactly random. it starts with a random population which the user defines. but then the algorithm will change the value, evaluate it, then again change value and evaluate it in an evolutionary process, until it satisfies my evaluation criteria. so it is imperative that i dun end up with a random selection everytime, then i wud not be anywhr close to the solution.
Hence when the algorithm alters the GENOTYPE node, there shouldnt be any overlapping selection. all the 64 genes must have unique number. is thr a way for the GENOTYPE node to check itself for its unique gene_no??
thanks a bunch!
Hence when the algorithm alters the GENOTYPE node, there shouldnt be any overlapping selection. all the 64 genes must have unique number. is thr a way for the GENOTYPE node to check itself for its unique gene_no??
thanks a bunch!
Houdini Indie and Apprentice » unique selection of primitives
- vigneshkaushik
- 20 posts
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hi,
attached is the .hip file. it contains a node called GENOTYPE. this node selects 64 primitives from a pool of 1000 primitives. however, im unable to find a solution to make it a unique selction for all the 64 primitives. for eg. all the 64 prim must take unique positions within the pool of 1000 and must not overlap. how to do this??
Pls help me with this problem!! thanks a tonne!
cheers
vignesh kaushik
attached is the .hip file. it contains a node called GENOTYPE. this node selects 64 primitives from a pool of 1000 primitives. however, im unable to find a solution to make it a unique selction for all the 64 primitives. for eg. all the 64 prim must take unique positions within the pool of 1000 and must not overlap. how to do this??
Pls help me with this problem!! thanks a tonne!
cheers
vignesh kaushik
Houdini Indie and Apprentice » help with HSCRIPT
- vigneshkaushik
- 20 posts
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{
# X is the gene number
# panel returns the number in the gene slider in GENOTYPE node
X = prim(“../each1”, 0, “primno”, 0);
panel = ch(“../../GENOTYPE/gene_`X`”);
return panel;
}
this code gives me an error in syntax in houdini.
the problem is with gene_X…is there a way to refer the value of X i get in the prev. line in the next line aling with a parameter name?? for example the value of X keeps changing from 1 to 500 and each time the it refers to the gene_X. I have attached the file
is there another way of writing this? Pls Help
# X is the gene number
# panel returns the number in the gene slider in GENOTYPE node
X = prim(“../each1”, 0, “primno”, 0);
panel = ch(“../../GENOTYPE/gene_`X`”);
return panel;
}
this code gives me an error in syntax in houdini.
the problem is with gene_X…is there a way to refer the value of X i get in the prev. line in the next line aling with a parameter name?? for example the value of X keeps changing from 1 to 500 and each time the it refers to the gene_X. I have attached the file
is there another way of writing this? Pls Help
Houdini Indie and Apprentice » attributes enquiry
- vigneshkaushik
- 20 posts
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have an attribcreate node and set it to detail-float. go to the value tab and hv the code written for the division of the two parameters.
Houdini Indie and Apprentice » parameters in 'edit parameter interface'
- vigneshkaushik
- 20 posts
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Thank you Jeff…i had used one of your examples to create one for my own…pls have a look at it and let me know if there are any problems that i might have to correct..thanks for ur help!
cheers
visika
cheers
visika
Houdini Indie and Apprentice » error in node inside FOREACH
- vigneshkaushik
- 20 posts
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There is an attribute create node called ‘panel’ inside the FOREACH which is a little problematic…it shows bad parameter reference to a node called GENOTYPE even though things seem alrite and infact works well once u keep refreshing the ‘panel’ node. But wen u open the file again, it shows bad parameter reference again. dunno wht the bug is!!
guys, can u pls help me out wit this? Thanks :-)
cheers
VISIKA
guys, can u pls help me out wit this? Thanks :-)
cheers
VISIKA
Houdini Indie and Apprentice » parameters in 'edit parameter interface'
- vigneshkaushik
- 20 posts
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I would like to know if we can make the parameters, say ‘a 42 integer’, duplicate itself, according to the no. of primitives in the group. To put it simply, I would like as many integer parameters as the no. of primitives in the group. If the no. of prim. change in the group, the no. of integer parameters has to change accordingly.
how to do this? Help me!
how to do this? Help me!
Houdini Indie and Apprentice » How to solve cache problems?
- vigneshkaushik
- 20 posts
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This is a school proj. i am working on. This is using the DOP network where im trying to use particles as agents with behaviour. In this particular file, im trying to attract particles of same color and repel particles of other colors.
The simulation runs for 15 frames after which it crashes. I think its due to cache overrun. Can anyone help me with solving the caching problem? I have attached the file. You can have a look at it.
The simulation runs for 15 frames after which it crashes. I think its due to cache overrun. Can anyone help me with solving the caching problem? I have attached the file. You can have a look at it.
Houdini Indie and Apprentice » Houdini crashing!! Segmentation Fault
- vigneshkaushik
- 20 posts
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i downloaded the latest version of houdini 11 from the free apprentice download. wen the installation is done, it is not throwing up the licence server dialog box like in normal cases. wen i try to open houdini and just put a sphere on to a scene, it crashes wit the error ‘segmentation fault’.
its a new machine..toshiba m645, nvidia geforce GT330M, n i have driver version 189.72, win 7 32 bit.
BTW, i also tried upgrading my graphic driver to 258.96. but still nothing works. Im able to open my licence sever and view my seriver name n code and apprentice licence for houdini master n escape…
can anyone let me know whts gng on and wht cud be the solution?
its a new machine..toshiba m645, nvidia geforce GT330M, n i have driver version 189.72, win 7 32 bit.
BTW, i also tried upgrading my graphic driver to 258.96. but still nothing works. Im able to open my licence sever and view my seriver name n code and apprentice licence for houdini master n escape…
can anyone let me know whts gng on and wht cud be the solution?
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