ok, Houdini uses arbitrary units right?
ive been testing a scene witha ball sitting on a grid with one shadow casting keylight..
when the ball is 1 unit in size and sitting on the grid, the shadows cast are in the right places, ie. in contact with the base of the sphere..
if i use uniform scale and reduce the size of the sphere to say… 0.3 (and ensure the ball is sitting on the grid as before) the accuracy goes astray, and the shadows are no longer in contact with the sphere, i cant find a shadow bias setting to adjust this problem.
this is an issue because the shots i`m working on vary wildly in scale i need some models in the sequence are a matter of centimetres high, and others a number of metres, i was planning of using 1 unit=1cm for shots where the small objects are used, and 1unit=1metre for the larger shots.
because if i used 1cm consistently the large objects will surely become a problem with z depthe accuracy, and vice versa if i use metres the small objects will become a problem.
could anyone help me figure this out, or give me some pointers as to how they generally work with units in houdini?
cheers,
Mark
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Technical Discussion » related to the shadow bias: unit scale.. hellllppp!!! :(
- MWainwright
- 119 posts
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Technical Discussion » shadow bias in non shop shadow shaders
- MWainwright
- 119 posts
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hi, i was just wondering if theres a shadow bias setting for z depth and fast shadows?
i can do it within a shop shadow shader, but not from a shadow shader aplied within light object.
any help appreciated, cheers,
Mark
i can do it within a shop shadow shader, but not from a shadow shader aplied within light object.
any help appreciated, cheers,
Mark
Technical Discussion » instancing lights onto geometry
- MWainwright
- 119 posts
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cool.. cheers..
i cant seem to find a shadow shader to do z depth shadows with the light instancing, theres a z depth softness option but it doesnt seem to do anything…
anyone any iddeas?
cheers,
mark
i cant seem to find a shadow shader to do z depth shadows with the light instancing, theres a z depth softness option but it doesnt seem to do anything…
anyone any iddeas?
cheers,
mark
Technical Discussion » instancing lights onto geometry
- MWainwright
- 119 posts
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Technical Discussion » bump map and displace map interfering
- MWainwright
- 119 posts
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simon - cheers, i`ll try playing with that… what seems especially strange though isthat i get the artifacts even if the displace is set to 0 bu stillt applied to the surface.
Technical Discussion » Particles with trail sop jumping to random points on frames
- MWainwright
- 119 posts
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hi all!!
i have a particle system /otl as follows…
particles spawned from a point group - which is created when spawn geometry enters a bounding box..
the velocity of the spawn geometry is passed into chops (via an object chop then a slope chop, channels are then split into x, y and z) where the user has access to multipliers and limits on the x, y and z velocity, these are then passed up to the particle systems birth rate and dvelocity attributes (throwing the partiles in the direction of th emoving geometry)
it all appears to work beautifully until a trail sop is applied (for motion blur) when this reveals that particles are zooming off at large velocities in random directions on some frames.. i have applied numerous limits to the particle velocites that are passed back up to the source pop, also there are no spikes in the slope data being passed through chops… i`vwe been trying to solve this for 2 days now with no luck..
anyone got any idea what might be causing this?
otherwise is there a way to use deformation / transformation motion blur on particles to see if its the trail sop causing the problem?
cheers all…
i have a particle system /otl as follows…
particles spawned from a point group - which is created when spawn geometry enters a bounding box..
the velocity of the spawn geometry is passed into chops (via an object chop then a slope chop, channels are then split into x, y and z) where the user has access to multipliers and limits on the x, y and z velocity, these are then passed up to the particle systems birth rate and dvelocity attributes (throwing the partiles in the direction of th emoving geometry)
it all appears to work beautifully until a trail sop is applied (for motion blur) when this reveals that particles are zooming off at large velocities in random directions on some frames.. i have applied numerous limits to the particle velocites that are passed back up to the source pop, also there are no spikes in the slope data being passed through chops… i`vwe been trying to solve this for 2 days now with no luck..
anyone got any idea what might be causing this?
otherwise is there a way to use deformation / transformation motion blur on particles to see if its the trail sop causing the problem?
cheers all…
Technical Discussion » baking/freezing a displacement to polys
- MWainwright
- 119 posts
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eee.. so much info.. i`m a bit lost!!
so do i have to build some kind of displace shader to bring my displacement to the poly level at sops? or just read something from my generic displace or my texture into a point sop?
so do i have to build some kind of displace shader to bring my displacement to the poly level at sops? or just read something from my generic displace or my texture into a point sop?
Technical Discussion » bump map and displace map interfering
- MWainwright
- 119 posts
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hey.. the bump shader is my own, but the displace is the generic displace… my bump is bumping by surface normal… (is there another way?)
Technical Discussion » different sprites based on SCREEN direction
- MWainwright
- 119 posts
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hi all.. i`m trying to find a way to make a sprite display a different texture based on its direction and speed based on screen coordinates.. ie, relative to eye (camera) so if it is moving fast across screen -x it displays one thing, and if its moving very slowly in scrren +x it displays another etc..
any help appreciated,
cheers,
Mark
any help appreciated,
cheers,
Mark
Technical Discussion » Problems with groups (invalid group message)
- MWainwright
- 119 posts
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i`m not sure what causes it, but if you create the group in the viewport, first by
tab>group > select a primitive > reselect geometry and select what you want > right mouse.
it seems to fix it.. initialising groups in the network editor seems to have a bug.
tab>group > select a primitive > reselect geometry and select what you want > right mouse.
it seems to fix it.. initialising groups in the network editor seems to have a bug.
Technical Discussion » baking/freezing a displacement to polys
- MWainwright
- 119 posts
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jason_iversen
You don't have the original source-code? If you do, change it from a displace mydisp() to a sop mydisp() and you'll compile a SOP with the same capabilities as the displacement shader.
Otherwise VOPs is an excellent alternative
ah.. i thought the code from the type properties, which i cant get at in generic displace.. just the string from teh generic displace?
all i see is
“dmap map $HIP/textures/final_1024/octopus_tent_disp.tif amp 0.05 forpoly 1”
i dont know how to build a displacement in vops.. *looks*
Technical Discussion » baking/freezing a displacement to polys
- MWainwright
- 119 posts
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hey! cheers… but i`m using generic displace so i cant get at the code.. should i build a displace in vexbuilder?
Technical Discussion » bump map and displace map interfering
- MWainwright
- 119 posts
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hi again!! i have both a bump and displace map applied to my model.. the bump map seems to be interfering with the displace map and resulting in fuzzy, speckly black rendering artifacts.. they dont occur when either one is turned off but when both on together they occur.
any ideas?
cheers again..
any ideas?
cheers again..
Technical Discussion » baking/freezing a displacement to polys
- MWainwright
- 119 posts
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hi all.. is there any way to take a model with a displacement map appled and bake the displacement into the model so it can be worked on post displacement ?
basically applying the displacement map to the points so that it can be seen in the viewport.
thanks..
basically applying the displacement map to the points so that it can be seen in the viewport.
thanks..
Technical Discussion » vops - opacity fading spec hilight and environment map.
- MWainwright
- 119 posts
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yeah, i want the opscity to only affect the diffuse.
the spec hilight and environment to remain unaffected, but when i change the opacity on that vopnet it definately makes ths spec hilight also transparent, alog with the environment map.. basically it affects everything,
the spec hilight and environment to remain unaffected, but when i change the opacity on that vopnet it definately makes ths spec hilight also transparent, alog with the environment map.. basically it affects everything,
Technical Discussion » vops - opacity fading spec hilight and environment map.
- MWainwright
- 119 posts
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Hi.. the way ive wired my vopnet means that opacity if also affecting my spec highlight and environment map.. how can i stop this from happening..
http://home.btconnect.com/symbiont-design/stuff/vopnet.jpg [home.btconnect.com]
cheers..
http://home.btconnect.com/symbiont-design/stuff/vopnet.jpg [home.btconnect.com]
cheers..
Technical Discussion » vops - controlling edge falloff vop
- MWainwright
- 119 posts
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Technical Discussion » vops - controlling edge falloff vop
- MWainwright
- 119 posts
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can anyone help me out.. i need to take control of the edge falloff vop.. so i need to be able to control the falloff and also invert the colours so that its lighter on the outside. what vops should i be looking at to do this?
cheers
cheers
Technical Discussion » refereshing textures
- MWainwright
- 119 posts
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how do you refresh the texture maps in a scene or object so that houdini reloads the image files?
Technical Discussion » more bump mapping artifacts
- MWainwright
- 119 posts
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