Found 13 posts.
Search results Show results as topic list.
Technical Discussion » Vellum constraint properties animation with expression
-
- bdav
- 13 posts
- Offline
Technical Discussion » Vellum constraint properties animation with expression
-
- bdav
- 13 posts
- Offline
Hi,
I'm trying to adjust the stiffness of a pin-to-target constraint with an expression : smooth($FF,1,48)

The problem is, it overrides completely the existing stiffness; doing @stiffness*smooth() or stiffness* smooth() doesn't work;
No big deal i thought, i just write in the vex code:
stiffness *= smooth($FF,1,48);
It doesn't work;
Now i figure out, there is 2 differents smooth fonctions: first one doesn't work in vex it seems, very confusing.


Well second smooth doesn't work either ! Any idea what i'm doing wrong? I could use some help here.
Thanks in advance
I'm trying to adjust the stiffness of a pin-to-target constraint with an expression : smooth($FF,1,48)
The problem is, it overrides completely the existing stiffness; doing @stiffness*smooth() or stiffness* smooth() doesn't work;
No big deal i thought, i just write in the vex code:
stiffness *= smooth($FF,1,48);
It doesn't work;
Now i figure out, there is 2 differents smooth fonctions: first one doesn't work in vex it seems, very confusing.
Well second smooth doesn't work either ! Any idea what i'm doing wrong? I could use some help here.
Thanks in advance
Technical Discussion » Pyro threshold vs control field
-
- bdav
- 13 posts
- Offline
Hi,
In the turbulence/disturbance settings, there is a threshold field and a control field.
Is there any difference between the two? I'm not sure i understand the help file about it.
thanks in advance
In the turbulence/disturbance settings, there is a threshold field and a control field.
Is there any difference between the two? I'm not sure i understand the help file about it.
thanks in advance
Technical Discussion » Changing viewport camera when switching takes
-
- bdav
- 13 posts
- Offline
Technical Discussion » Changing viewport camera when switching takes
-
- bdav
- 13 posts
- Offline
Hi,
I have a scene with two takes, Cam1 for take1 and Cam2 for take2. When switching takes, the viewport stay on Cam1 for example, how can I switch cam automatically?
I have a scene with two takes, Cam1 for take1 and Cam2 for take2. When switching takes, the viewport stay on Cam1 for example, how can I switch cam automatically?
Work in Progress » Old home. Procedural modeling
-
- bdav
- 13 posts
- Offline
Work in Progress » Tree growth phyllotaxy - an experiment
-
- bdav
- 13 posts
- Offline
Work in Progress » Tree growth phyllotaxy - an experiment
-
- bdav
- 13 posts
- Offline
Thanks Malbrecht
Sounds great, did you compute illumination in sop context?
would love to see some screens!
Sounds great, did you compute illumination in sop context?
would love to see some screens!
Work in Progress » Tree growth phyllotaxy - an experiment
-
- bdav
- 13 posts
- Offline
Work in Progress » Tree growth phyllotaxy - an experiment
-
- bdav
- 13 posts
- Offline
Some various tests and renders of a little 2-3 month personal project, to practice houdini and vex.


This is inspired by - obviously - the great A. Opara talk about biological tree growth, and that push me to implement my own take on it, surely not as elegant nor efficient tho!
I started with the idea of an avoidance model, based on an modified version of the ambient occlusion vex code (sop context) from Tokeru wiki, so many kudos to Matt Estela and the awesome tokeru wiki, which taught me the base of vex for many months (love the gifs!).
The pseudocode for the growth is:
only on active points
check next possible positions within a cone
accumulate occlusion for each possible points
choose the one with the least occlusion and set new direction
blend with previous direction
check chance to split in branches and spawn new active points with correct orient
grow toward new direction based on apical ratio, occlusion, iterations, stepsize, etc…
Features for now:
- geo avoidance (random or even search points)
- branch angle, tropism & gravity influence
- codominance chance (need work)
- break chance of branches based on length (need rework)
- Root system
- leaves instancing, no sim for now but its fast
- generated geo + uv with sweep (tokeru wiki was a great help here once again)
- wire sim + procedural constraints
- geo capture with for-each branches id + wirecapture
- wind affecting wire sim + fake leaves movement (for speed)
It's not as art-directable as some more traditional tree modeling method, but i had a lot of fun developing this one and adding features.
Todo:
- simplify parameters (way too many to be really practical)
- rework of the random branch cut, impact the growth time calculation too much because of the foreach within foreach
- better handling of codominant branches geo creation ? uv looks bad
- surface attraction for ivy-style effect
- code and network clean-up cause it's a mess and some attributes are not used anymore
- better leaf generator
- …
When i first started, the plant only divided when enough amount of energy was accumulated on active points, then splitting would drain some energy. It was somehow quite uncontrolable but produced some crazy result. I even implemented a graph monitoring energy for that, I would like to fix it at some point.

Thanks for your attention and, in advance, sorry for any engrish in the text ! (not a native english speaker)
more render tests here [www.artstation.com]
This is inspired by - obviously - the great A. Opara talk about biological tree growth, and that push me to implement my own take on it, surely not as elegant nor efficient tho!
I started with the idea of an avoidance model, based on an modified version of the ambient occlusion vex code (sop context) from Tokeru wiki, so many kudos to Matt Estela and the awesome tokeru wiki, which taught me the base of vex for many months (love the gifs!).
The pseudocode for the growth is:
only on active points
check next possible positions within a cone
accumulate occlusion for each possible points
choose the one with the least occlusion and set new direction
blend with previous direction
check chance to split in branches and spawn new active points with correct orient
grow toward new direction based on apical ratio, occlusion, iterations, stepsize, etc…
Features for now:
- geo avoidance (random or even search points)
- branch angle, tropism & gravity influence
- codominance chance (need work)
- break chance of branches based on length (need rework)
- Root system
- leaves instancing, no sim for now but its fast
- generated geo + uv with sweep (tokeru wiki was a great help here once again)
- wire sim + procedural constraints
- geo capture with for-each branches id + wirecapture
- wind affecting wire sim + fake leaves movement (for speed)
It's not as art-directable as some more traditional tree modeling method, but i had a lot of fun developing this one and adding features.
Todo:
- simplify parameters (way too many to be really practical)
- rework of the random branch cut, impact the growth time calculation too much because of the foreach within foreach
- better handling of codominant branches geo creation ? uv looks bad
- surface attraction for ivy-style effect
- code and network clean-up cause it's a mess and some attributes are not used anymore
- better leaf generator
- …
When i first started, the plant only divided when enough amount of energy was accumulated on active points, then splitting would drain some energy. It was somehow quite uncontrolable but produced some crazy result. I even implemented a graph monitoring energy for that, I would like to fix it at some point.
Thanks for your attention and, in advance, sorry for any engrish in the text ! (not a native english speaker)
more render tests here [www.artstation.com]
Edited by bdav - 2019年2月14日 18:52:37
Technical Discussion » Troble with shading ocean
-
- bdav
- 13 posts
- Offline
Had the same problem, no displacement at rendertime. Make sure you bake the spectra, that fixed it for me. Hope that help.
Houdini Learning Materials » Smooth based on attribute
-
- bdav
- 13 posts
- Offline
Houdini Learning Materials » Smooth based on attribute
-
- bdav
- 13 posts
- Offline
Hello Everyone
I'm currently learning Houdini Apprentice and really enjoy the workflow and possibilities of the software.
I'm working on a erosion effect and can't figure how to smooth based on an attribute or color, the group selection from attribute doesn't really work because the transition are really rough. I tried blendshape but I can't restrict the blend based on a point attribute either.
If anyone got a idea how to achieve this I would be really thankful
Thanks for your help
Edit:typo
I'm currently learning Houdini Apprentice and really enjoy the workflow and possibilities of the software.
I'm working on a erosion effect and can't figure how to smooth based on an attribute or color, the group selection from attribute doesn't really work because the transition are really rough. I tried blendshape but I can't restrict the blend based on a point attribute either.
If anyone got a idea how to achieve this I would be really thankful
Thanks for your help
Edit:typo
-
- Quick Links