Yeah, Subdiv SOP works, but I really don't like the overhead, and I need better displacements. It's not just Michael's file that won't render as subd, my own files don't work either.
By painting transparency did you mean painting by hand in photoshop?
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Technical Discussion » transparency fade off for overlapping multi-layer shaders
- Siavash Tehrani
- 710 posts
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Technical Discussion » transparency fade off for overlapping multi-layer shaders
- Siavash Tehrani
- 710 posts
- Online
Technical Discussion » transparency fade off for overlapping multi-layer shaders
- Siavash Tehrani
- 710 posts
- Online
Sorry for resurrecting such an old topic, but I have a little problem. ops:
I'm using the method that JC described and Michael put up in the example file. Everything works great, and it's really nice to be able to paint masks directly onto the geometry, but, when I render as subdivision surfaces mantra quits halfway through, which also causes mplay to hang. Works fine when I render as polys. Does this happen to anyone else? I'm still using 6.1.149 so maybe this is something that's been resolved in newer versions?
I'm using the method that JC described and Michael put up in the example file. Everything works great, and it's really nice to be able to paint masks directly onto the geometry, but, when I render as subdivision surfaces mantra quits halfway through, which also causes mplay to hang. Works fine when I render as polys. Does this happen to anyone else? I'm still using 6.1.149 so maybe this is something that's been resolved in newer versions?
Houdini Lounge » Crowd Sim Model
- Siavash Tehrani
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That's pretty cool Nate, is it a hover-bike?
edit: nevermind maybe I should read the post. ops:
So you're gonna have a bunch of these in a crowd sim?
edit: nevermind maybe I should read the post. ops:
So you're gonna have a bunch of these in a crowd sim?
Houdini Lounge » Color gradients via Displacement
- Siavash Tehrani
- 710 posts
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That's pretty cool dobe. A proper gradient ramp in VOPs wouldn't be a bad idea.
I was trying it again diya and I'm not sure how to import the combined values of the displace VOPs into the surface context. I guess that's the only problem, because then you could take that value and plug it into the bias of a color mix vop. A gradiant ramp vop with multiple inputs would be nice, instead of having to build a tree of color mix vops to get a bunch of different layers.
I was trying it again diya and I'm not sure how to import the combined values of the displace VOPs into the surface context. I guess that's the only problem, because then you could take that value and plug it into the bias of a color mix vop. A gradiant ramp vop with multiple inputs would be nice, instead of having to build a tree of color mix vops to get a bunch of different layers.
Houdini Lounge » Color gradients via Displacement
- Siavash Tehrani
- 710 posts
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Sorry diya, haven't had much time to try it. What other software have you acomplished this effect in? Could you upload a picture made in another app, it would give me a more clear idea, and I could try to match the results more closely.
Houdini Lounge » Color gradients via Displacement
- Siavash Tehrani
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No problem diya, I learned some stuff myself during this exercise. I think I understand your idea now. You want the displacement of the various VOPs as one big acumulative value in your surface shader, correct? You are right about needing to copy all the VOPs from the displace context to the surface context with my example, so in it's not as automated as your idea. You can still divide the ranges in this shader using some Color Mix VOPs, that's not a problem. For example the yellow/green base of the “hills” could be several layers.
I don't have Houdini in front of me right now, but I'll see if I can figure out your idea later.
I don't have Houdini in front of me right now, but I'll see if I can figure out your idea later.
Houdini Lounge » Apprentice Challange and SIGGRAPH04 questions
- Siavash Tehrani
- 710 posts
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Technical Discussion » How come OpenGL crash issues on WinXP have not been fixed?
- Siavash Tehrani
- 710 posts
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David, what do you mean by OpenGL crashing? I've been having a problem where after a while of working in SOPs, the viewport will stop working correctly. For example I select some points but when I right-click the transform handle won't come up. Or some SOPs will stop working on highlighted geometry, for example Poly-Knit. Houdini doesn't crash though, I just have to restart it.
And every once in a great while, and at random times in the session, Houdini will freeze, and freeze for good. You can tell because when you look at the task manager it will only be using about 1.5 megs of ram. You have to forcefully exit the app and you do loose work.
I haven't really experienced what you described though with files getting corrupted.
And every once in a great while, and at random times in the session, Houdini will freeze, and freeze for good. You can tell because when you look at the task manager it will only be using about 1.5 megs of ram. You have to forcefully exit the app and you do loose work.
I haven't really experienced what you described though with files getting corrupted.
Houdini Lounge » OSX?
- Siavash Tehrani
- 710 posts
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Yeah, waste kinda makes it sound like OSX sucks or something, but I just meant that there doesn't seem to be much demand for Houdini on OSX from current commercial users, so why “spend” the resources.
Are Solaris and IRIX versions still in the future or have they been officially canned? That would be sad, but I guess on the plus side it's a bit (or a lot?) easier for sesi having to focus only on Win and Linux versions.
Are Solaris and IRIX versions still in the future or have they been officially canned? That would be sad, but I guess on the plus side it's a bit (or a lot?) easier for sesi having to focus only on Win and Linux versions.
Technical Discussion » Repository for L-System rules?
- Siavash Tehrani
- 710 posts
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Err, can't really help you with your question, sorry, but I found this last night. I can't read Korean so it's not very useful to me, but what the heck…
http://www.houdini.co.kr/tutorial/lsystem/lsys2.html [houdini.co.kr]
http://www.houdini.co.kr/userguide/l-system/l-system-1.htm [houdini.co.kr]
http://www.houdini.co.kr/tutorial/lsystem/lsys2.html [houdini.co.kr]
http://www.houdini.co.kr/userguide/l-system/l-system-1.htm [houdini.co.kr]
Houdini Lounge » OSX?
- Siavash Tehrani
- 710 posts
- Online
If you read the mail archives there are some very recent posts about it. Seems that unless a major studio asks for it, they are not going to waste any resources on an OSX port.
Houdini Lounge » Color gradients via Displacement
- Siavash Tehrani
- 710 posts
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Hmm, maybe this one is more what you're looking for. Not exactly realistic terrain but it has planes, valleys, and peaks…well…sort of. I think you'll have to get nitty gritty with it to see if it works out for you…
http://www.geocities.com/stehrani3d/3dfiles/terrain_shader.zip [geocities.com] (Right Click>Save Target)
Couple of notes on the file: If you look at surface shader, a couple of the VOPs have their paramaters all green, and you can't change the values. That's because those values are channel referenced to their duplicate VOPs in the displace shader. So if you change a parameter in the Soft Dots VOP under terrain_displace, it will automatically change that same parameter in the Soft Dot VOP under terrain_color. For some reason, it doesn't automatically update the change in the VOPs viewer, idunno, maybe a bug in 6.1.149. If you try to change a value it will update to show the correct state. Also if you see any VOPs with blue text (not light blue/purple) that means you can middle click to read comments I added. You probably already knew that but I just thought I'd mention.
http://www.geocities.com/stehrani3d/3dfiles/terrain_shader.zip [geocities.com] (Right Click>Save Target)
Couple of notes on the file: If you look at surface shader, a couple of the VOPs have their paramaters all green, and you can't change the values. That's because those values are channel referenced to their duplicate VOPs in the displace shader. So if you change a parameter in the Soft Dots VOP under terrain_displace, it will automatically change that same parameter in the Soft Dot VOP under terrain_color. For some reason, it doesn't automatically update the change in the VOPs viewer, idunno, maybe a bug in 6.1.149. If you try to change a value it will update to show the correct state. Also if you see any VOPs with blue text (not light blue/purple) that means you can middle click to read comments I added. You probably already knew that but I just thought I'd mention.
Houdini Lounge » Color gradients via Displacement
- Siavash Tehrani
- 710 posts
- Online
Hey diya, I'm not a veteran, but here's a really basic way to do it. I'm sure there's more advanced ways that tie in better to whatever displace shaders you have. This one just does a gradual ramp in the y-axis.
And the file (Right Click>Save Target)…
http://www.geocities.com/stehrani3d/3dfiles/height_shader.zip [geocities.com]
And the file (Right Click>Save Target)…
http://www.geocities.com/stehrani3d/3dfiles/height_shader.zip [geocities.com]
Technical Discussion » Making particles interact with displaced objects?
- Siavash Tehrani
- 710 posts
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Cheers Mario, you rock.
I updated the file slightly for anyone else who wants to check it out. Just deleted the old stuff from my previous attempt, plugged the particles back in, and used randomized geometry for the instances (props to aracid over at odforce for showing me how it works).
http://www.geocities.com/stehrani3d/3dfiles/particle_displace_updated.zip [geocities.com] (Right Click>Save Target)
I updated the file slightly for anyone else who wants to check it out. Just deleted the old stuff from my previous attempt, plugged the particles back in, and used randomized geometry for the instances (props to aracid over at odforce for showing me how it works).
http://www.geocities.com/stehrani3d/3dfiles/particle_displace_updated.zip [geocities.com] (Right Click>Save Target)
Technical Discussion » Making particles interact with displaced objects?
- Siavash Tehrani
- 710 posts
- Online
Thank you for all the excellent suggestions, but I'm really confused as how to implement the whole thing.
I'm using the Collision POP to get hitpos, hituv, and hituvpos, not sure which ones I actually will need. But I don't know their usage in VOPs, can I just import them with the Parameter VOP? They seem to react like a normal Parameter VOP when I plug them in here and there, so I'm doubtful the attributes have actually been succesfully imported. Could this have something to do with the fact that those attributes only have values after a certain frame (once the particles hit the collision object)? And assuming I have the necessary attribute in VOPs, where in the network would it be used? In place of regular uv coords?
Another thing, For my instance geometry I have an Add SOP going into a Copy SOP, with the Pop Merge going into the template input. This just yields a grid of points, which I later plan to instance the actual stone models to. For now, these points are what I actually want to displace with a vex geo sop, as it seems like the easiest method. I noticed that some Vex SOPs don't work on points alone, including a test SOP I made. For example the standard Vex Mountain SOP has no effect, but if I PolyKnit some polygons on the grid, those areas suddenly become affected. The Vex Ripple SOP on the other hand works fine on just points alone.
I have uploaded the test scene, if anyone cares to take a look at it.
Thank you.
http://www.geocities.com/stehrani3d/3dfiles/particle_displace.zip [geocities.com] (Right Click>Save Target) made in 6.1.149 btw
I'm using the Collision POP to get hitpos, hituv, and hituvpos, not sure which ones I actually will need. But I don't know their usage in VOPs, can I just import them with the Parameter VOP? They seem to react like a normal Parameter VOP when I plug them in here and there, so I'm doubtful the attributes have actually been succesfully imported. Could this have something to do with the fact that those attributes only have values after a certain frame (once the particles hit the collision object)? And assuming I have the necessary attribute in VOPs, where in the network would it be used? In place of regular uv coords?
Another thing, For my instance geometry I have an Add SOP going into a Copy SOP, with the Pop Merge going into the template input. This just yields a grid of points, which I later plan to instance the actual stone models to. For now, these points are what I actually want to displace with a vex geo sop, as it seems like the easiest method. I noticed that some Vex SOPs don't work on points alone, including a test SOP I made. For example the standard Vex Mountain SOP has no effect, but if I PolyKnit some polygons on the grid, those areas suddenly become affected. The Vex Ripple SOP on the other hand works fine on just points alone.
I have uploaded the test scene, if anyone cares to take a look at it.
Thank you.
http://www.geocities.com/stehrani3d/3dfiles/particle_displace.zip [geocities.com] (Right Click>Save Target) made in 6.1.149 btw
Technical Discussion » Making particles interact with displaced objects?
- Siavash Tehrani
- 710 posts
- Online
Thanks Antoine, the second option sounds pretty intriguing! I'll have a shot at it and see how far I can get before getting stuck.
Technical Discussion » Making particles interact with displaced objects?
- Siavash Tehrani
- 710 posts
- Online
Antoine, the problem is that I plan to copy a lot of very small geometry (think small pebbles/stones) over a very large area, and I'm afraid that much of that geometry will end up below, or floating above the surface if the res is not high enough. Take a look at the pic, the little yellow box is supposed to be the scale of a human being, now imagine a small stone sitting next to it. Obviously the terrain would need to be subdivided A LOT more, otherwise any displacement map would alter the surface of the terrain too much for the pebbels/stones to appear where they're supposed to be.
Mark, sounds sorta interesting, but I wouldn't know where to begin.
So basically, particles and subdivision surfaces don't play together?
Mark, sounds sorta interesting, but I wouldn't know where to begin.
So basically, particles and subdivision surfaces don't play together?
Technical Discussion » Making particles interact with displaced objects?
- Siavash Tehrani
- 710 posts
- Online
Yeah, that was the first option, but it's just not feasable in this case. I have an environment modeled and to get the mesh detailed enough I estimate it would have to be between 12million to 48million polygons. :shock:
Technical Discussion » Making particles interact with displaced objects?
- Siavash Tehrani
- 710 posts
- Online
Is this possible? Say I have some particles that are dropping on a surface and sticking to it. Now the surface is just a flat default grid but it has a displacement shader applied that makes it look like terrain when rendered. The problem is that the particles will only see the orginal flat grid and not the displaced render-time version. Is there some way to get the particles to recognize and interact with the micro-poly geometry?
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