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Technical Discussion » mental ray and houdini
- sl0throp
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Being a big mental ray user who uses the mia_materials all the time when I am using Maya…I only wish I was using Mantra instead or at least had a vops like workflow and nodes. Mia and mr are great single minded shaders but playing with vex and vops is the best kinda fun in shader land.
Technical Discussion » Collision of fluid particles?
- sl0throp
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I took a quick look at you file…
There is no collision object even in your autodop network, the only thing that is in your autodop network in the particle fluid emitter and the various stuff that goes along with it.
In your case create your collision geometry at the object level, select it and under rigid bodies select static object. Once done dive into the autodop network and you should see a new branch with a static object, a rigid body solver and a new merge node.
Under the collsion tab of the static object click on “show Guide geometry” and you should see the collision representation of the geometry. If it is not what it should look like up the resolution of the collisions until it is done.
Notice in this example I have just disable gravity by selecting the node above it and siming from that. If you want gravity just turn it on and rotate the geo so it collides.
There is no collision object even in your autodop network, the only thing that is in your autodop network in the particle fluid emitter and the various stuff that goes along with it.
In your case create your collision geometry at the object level, select it and under rigid bodies select static object. Once done dive into the autodop network and you should see a new branch with a static object, a rigid body solver and a new merge node.
Under the collsion tab of the static object click on “show Guide geometry” and you should see the collision representation of the geometry. If it is not what it should look like up the resolution of the collisions until it is done.
Notice in this example I have just disable gravity by selecting the node above it and siming from that. If you want gravity just turn it on and rotate the geo so it collides.
Technical Discussion » Gravity on impact only
- sl0throp
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“Or you could use the dophassubdata() to gain access to what has had collisions, then group those and use that group in a gravity force. Not sure how that would look on a supposedly breaking object though.”
This sounds about right thnx.
s
This sounds about right thnx.
s
Technical Discussion » Gravity on impact only
- sl0throp
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I am trying to set up a glass skylight break sim and all is working great except I only want to have gravity affect an rbd piece if it has impact so my skylight won't fall as a group. I am pretty sure that I can cull the impact data somehow, put it into a group that gravity will affect I am just unsure how to proceed.
Any help or guidance here would be great.
s
Any help or guidance here would be great.
s
Houdini Lounge » Attach Geometry to Particles
- sl0throp
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Hope this helps. This is pretty basic but you could control how the particles are copied to the geo in a variety of ways with a little investigation.
s
s
Houdini Lounge » Attach Geometry to Particles
- sl0throp
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use the copy sop with the geo to be copied into input one and particle system into input two. That's about it for a basic put this geo onto particles.
s
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Technical Discussion » linear workflow
- sl0throp
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Truthfully this is the exact same work flow that someone would have to follow to get a linear flow working correctly in Maya, the only difference is that in mental ray they are using a tone mapper, in this case mia_exposure_simple to render into at gamma 2.2. This tome mapper than either needs to be deleted or rendered in non tone mapped buffers.
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Houdini Lounge » Best way to composite planes from a.exr or .pic in halo ?
- sl0throp
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You should check out the Nuke forum over at vfxtalk…since this is the most capable multi plane exr compositor out there there is lot's of data that will carry over to comping in Houdini as the nodes are the same..add, mult, etc. Also working in 32 bit float linear light is important here.
This is not to say don't pick up that Brinkman book - the only real comping book that I have seen.
s
This is not to say don't pick up that Brinkman book - the only real comping book that I have seen.
s
Houdini Lounge » Best way to composite planes from a.exr or .pic in halo ?
- sl0throp
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You should check out the Nuke forum over at vfxtalk…since this is the most capable multi plane exr compositor out there there is lot's of data that will carry over to comping in Houdini as the nodes are the same..add, mult, etc. Also working in 32 bit float linear light is important here.
This is not to say don't pick up that Brinkman book - the only real comping book that I have seen.
s
This is not to say don't pick up that Brinkman book - the only real comping book that I have seen.
s
Technical Discussion » White background?
- sl0throp
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you do not need a cylinder (huh?)- use a cyc like the other person said - a cyc if you do not know is just two perpendicular planes connected by a radius and are usually found in photo studios and are made for this reason. Sometimes I will also rather than have two planes, use a revolve - like a hemisphere with a radius ed edge where it meets the ground plane.
Also I would look into ambient occlusion shading…
s
Also I would look into ambient occlusion shading…
s
Houdini Lounge » Integration tutorials?
- sl0throp
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Technical Discussion » Lsystem & Bones
- sl0throp
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David Grey has a great tutorial for this tho' no bones involved on the L-systems DVD's at CMI.
All great DVD's btw.
S
All great DVD's btw.
S
Technical Discussion » Shattering Geometry procedurally
- sl0throp
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Yes I understand the trace sop I think but what I want to do is to affect an already existing piece of geometry not to define geo through a trace sop. Like lets say a cup, is it possible to define shader through vex that will allow me to break that object apart based upon the structure that would be defined by the noise pattern almost like using it as trims.
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Technical Discussion » Shattering Geometry procedurally
- sl0throp
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Technical Discussion » Shattering Geometry procedurally
- sl0throp
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After reviewing the digital tutors dynamics DVD, there is an example of how they shatter an object by using the paint tool to separate the shards out into multiple groups based on color.
This got me thinking on if and how it would be possible to do this by rather than paint use something like a varnoi noise function in vops similar to what frenchie op ( His are the best vtm's out there and I owe him a lot of gratitude for the knowledge he shares) does in his procedural cities dvd's. You would have procedural control over the celular pattern that was generated and use that to somehow manipulate the points to separate the geometry into groups this way.
I am just not sure exactly how to go about it…or is there a better way
s
This got me thinking on if and how it would be possible to do this by rather than paint use something like a varnoi noise function in vops similar to what frenchie op ( His are the best vtm's out there and I owe him a lot of gratitude for the knowledge he shares) does in his procedural cities dvd's. You would have procedural control over the celular pattern that was generated and use that to somehow manipulate the points to separate the geometry into groups this way.
I am just not sure exactly how to go about it…or is there a better way
s
Houdini Lounge » simple question about "copy" from maya user
- sl0throp
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Sound to me like you are not creating your object in context when you are not using the shelf icons. So when you try to do it w/o the shelf and hook it up your self you create a box and a grid but without create in context the box and the grid are in separate networks. If you look just under the shading menu in the scene view you will see a button that creates a menu that allows you to create in context or not. What this basically means is…in context all stuff exist under one network. not in context means that for every object you create you create separate networks.
could be wrong here but hope it helps…
Jordan
could be wrong here but hope it helps…
Jordan
Houdini Lounge » Maya to Houdini Modeling questions...
- sl0throp
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I have a few simple questions that I have not found easy answers for any help or points in the right direction would appreciated.
1. In Maya I can specify a loft as either linear or cubic. I would like to create lofts with multiple closed curves where the interpolation is linear between spans and does not result in a smoothed shape and perfectly intersects the spans.
2. In Maya I can specify a normal angle to poly objects(0-180) to specify hard or soft normals. I can not figure out how to replicate this in Houdini.
3. In general what is a good approach towards Hard Surface UV mapping? I am working through the UV tutorials that just came out but they are geared more towards organic UV mapping.
4. As a general question what is a good coneptual workflow for the creation of hard surface polygonal geometry? Like as an example. Create Box, Extrude faces, Fuse and Clean Up thena apply UV's.
5. How can I transform a face or a series of points perpindicular to the normal of the object rather than world space?
Thanks for any help
s
1. In Maya I can specify a loft as either linear or cubic. I would like to create lofts with multiple closed curves where the interpolation is linear between spans and does not result in a smoothed shape and perfectly intersects the spans.
2. In Maya I can specify a normal angle to poly objects(0-180) to specify hard or soft normals. I can not figure out how to replicate this in Houdini.
3. In general what is a good approach towards Hard Surface UV mapping? I am working through the UV tutorials that just came out but they are geared more towards organic UV mapping.
4. As a general question what is a good coneptual workflow for the creation of hard surface polygonal geometry? Like as an example. Create Box, Extrude faces, Fuse and Clean Up thena apply UV's.
5. How can I transform a face or a series of points perpindicular to the normal of the object rather than world space?
Thanks for any help
s
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