R8 :: Xpresso and Materials

[Srek]

Hi,
sorry but this will have to wait for a later version. Right now you can modify practically every parameter of the materials and the standard shaders within Xpresso so this should keep you entertained for a while :)
Regards
Srek

[Per-Anders]

actually... i should chagne that, after experimentation i don't see how i'm meant to get an output from "user data" or how i'm meant to get a value into a gradient in an xpresso group... i'd like to know how... and then i'd like to know how i can define which point on a gradient/texture is being sampled to give an output.

also i can drive the index of refraction of a texture with a value... is it possible to drive it at rendertime so that the ior can be "textured" with some formula or random noise or whatever?

[LucentDreams]

Originally posted by mdme_sadie
actually... i should chagne that, after experimentation i don't see how i'm meant to get an output from "user data" or how i'm meant to get a value into a gradient in an xpresso group... i'd like to know how... and then i'd like to know how i can define which point on a gradient/texture is being sampled to give an output.

also i can drive the index of refraction of a texture with a value... is it possible to drive it at rendertime so that the ior can be "textured" with some formula or random noise or whatever?

Haven't done much with expresso my self uyet, but if you find a way to do that I would concede in any *ahem* discussion we have ever had or will have :)

By the way I think you'll like this one, have you checked out the standard gradient shader, I think you'll like the changes made to it ;) no need for the ol powergradient anymore. unfortunately that means XL 7 scenes using powergradient will not be fully compatible, yo will need to take note of settings and reinput them into the new gradient shader.

[Srek]

Hi,
User Data can be accessed by placing the object in the Xpresso editor and simply using the Data Field as an In- or Output Port.
Refraction is available as a Port in the same way. Just D&D the Material in the Xpresso Editor and you get access to the Materials Parameters.
Regards
Srek

[ThirdEye]

I don't know if I have understood well but... there will be the possibility to map also the refraction channel? Am I wrong?

[Srek]

Hi,
there is no such thing as a refraction channel, but the refraction value can be animated either by using the timeline or Xpresso
Regards
Srek

[Per-Anders]

i'm having lots of fun here... and i notice that even though some things can't be animated... i can set driven keys on them (pretty damn awesome stuff)... although not everything seems to reflect this... hehe i tried to drive the bump texture with the colour texture on a material. oops, although it did make a connection when i tried to drive the ior with a colour texture in the same material... i can see this will be very powerful once the later version you're talking about comes out srek. i hope i'll be able to do this. also when a node turns yellow what does that mean? (have i tried to input a bad parameter?) also i was playing around with the poly node, again with textures, seeing if i could use the poly normal to make a fresnel effect (same as facing ratio in maya)... but i don't know how to drive the poly index to evaluate all polys.. any clues, or am i playing around too much with texture stuff that's still in development? all the same i'm having a whole heap of fun here. :)

[RickBarrett]

yellow node = error

this happens when you create an invalid connection or pass invalid data to a node.

[Srek]

The Iterator node is meant for this but i strongly recommend getting used to the more basic Xpresso stuff first :)
For the use of this have a look here: http://www.bonkers.de/r8/xp/xp_deformer.c4d
It's a very simple deformer i build using Xpresso.

Have Fun
Srek

[LucentDreams]

Originally posted by mdme_sadie
i'm having lots of fun here... and i notice that even though some things can't be animated... i can set driven keys on them (pretty damn awesome stuff)... although not everything seems to reflect this... hehe i tried to drive the bump texture with the colour texture on a material. oops, although it did make a connection when i tried to drive the ior with a colour texture in the same material... i can see this will be very powerful once the later version you're talking about comes out srek. i hope i'll be able to do this. also when a node turns yellow what does that mean? (have i tried to input a bad parameter?) also i was playing around with the poly node, again with textures, seeing if i could use the poly normal to make a fresnel effect (same as facing ratio in maya)... but i don't know how to drive the poly index to evaluate all polys.. any clues, or am i playing around too much with texture stuff that's still in development? all the same i'm having a whole heap of fun here. :)

Yuu'llalso notice that almost anything can beanimated, want to animate a setting in the posteffects, rightclick and see if it says add keyframe, if it does it can be animated. so much control now. and things that don't even seem logical to animate can be animated like the edge setting in the cel render, its not like it fades the edge on and off, but it does turn them on and off. I doubt I'll use that but you never know

[Per-Anders]

is there any way to access user data on other (non object) nodes as inputs or outputs? you can't access all the nodes in the object browser, and if you put user data on a non object node it doesn't wanna show in the inputs/outputs. (at least for me, although i like the feature of being able to keyframe things such as the position of a colour on a gradient :thumbsup: )

[RickBarrett]

I noticed this earlier today, but now the user data is consistently showing up. Try using the user data in a set-driver / set-driven combo and see if that changes anything.

- Rick -

[Per-Anders]

thanks for the c4d file srek :) ... i see how it works, am i right in thinking that you could use it as the basis for a water "wake" type effect if you were to play around with a memory nodes and such like?

[Per-Anders]

ok, well at least now i know what parameters i'm able to work within. as far as using textures goes in xpresso, currently it's not able to evaluate during the render itself (i.e. there's no pixel matrix, or to put it another way, no uv values, so i don't see any way of convoluting a gradient for example by the polygon normals to create fresnel effects, or to create your own shaders) so xpresso in it's current form can't change a direct pixel point colour, only the overall colour, or a paramter overall on a frame by frame basis. although i suspect this wont always be this way... when either a node based texture system comes out for it, or it get's upgraded to being able to do this... you know who'll be first in line with his bank manager in despair! ;)

i wonder, is it possible to drive a vertex map and at least control colour blending between two shaders via xpresso? hmmm... am almost certain it must be possible... now to go and experiment some more :)

[Srek]

Honestly i think Coffee or C++ are much more suited for a task like the water wake. More complexe Texture calculations/actions will need several changes in the material system. The thre main points we had in mind while developing Xpresso were Character Animation, Thinking Particles and a more mechanical kind of animation. For a nice example on the later one have a look at Thomas Kunerts Homepage http://www.thomaskunert.de/
in the gallery he's showing a stam engine controlled by Xpresso.
Regards
Srek

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