Bouncelights effect with Gradients

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  10 October 2004
Thanks, much appreciated.

Unfortunately, it was as I suspected, a windows only plug.Ya do get bitten from time to time on this one.

Thanks I appreciate your response though.

Cheers
 
  10 October 2004
Gerardo's Method + New GI tools

Originally Posted by gerardo: mmm...lemme see
Gerardo
Hi all,
i use a similar thechnique for interiors, but slightly different.
I use Interpolated radiosity (1 bounce) with relatively low settings (i.e 0.3 and 300 mm), Motion Blur and EhnLow or EhnMedium AA. That's the "basis", then i work with gradients to get dimmer effects wich i cannot get with just 1 bounce.
Tha advantage is you have NOT to recreate the whole lighting, but you've just to tweak it.
Generally, i get 3-5h renderings at 2560x2048 (even with reflective floors) on a P4 3.0ghz 1MB ram. BTW, Gerardo's method gives you more control and is well suited for animation.

Here's a tool i'd been dreaming for years, maybe someone can develop it... i'm disposed to pay for it, and i think other will: kinda a "local ambient tool" controlled via objects + Vmaps. Gerardo's method is similar, but it involves much more handjob.
We should create a simple object compenetrating the scene (even a point cloud), putting points where we need. Then, we should assign a Vmap to this obj, setting values for each vertex.
In Layout, this "Cage" would be invisible, but a proper Shader should read Vmap values from each point, and assign a proportional value to Surface's ambient (and/or diffuse). The space between points would be linearly or spline interpolated.
Again, it'd be nice if we could assign a Color Vmap to each vertex of the "Cage" in order to simulate color bleeding. Again, tweaking would be easy as adding/deleting/moving points from the "cage", or changing Vmap values. The good thing is you control the whole scene lighting with just one control object. Again, "cage" obj can be animated via bones, endomorophs or displacement to get smoother or weird lighting effects...
I think this would give much more control and much faster GI tweaking to LW users. What do you think about it ?

Regard,
Paolo Zambrini
 
  10 October 2004
Hi Paolo,
Thank you to share your technique
I find the idea of the plug-in which you mention very interesting, I would add to your idea that this shader should also mix depending on different Input_Parameters; depending on each vertex or point and to be able to assign more than one Input_parameter per point.
Maybe even a plug like this could use the colors of a captured environment map from the scene, as a baked texture and applied to a vertex_colormap, but with the advantage of being able to be controlled with gradients (something that can also be used to integrate CG elements on live action plates)



Gerardo
 
  10 October 2004
Hi Gerardo,
yesterday i was trickin' about this, and i made some tests.
Maybe you know Weighter plugin (commercial), which allows Vmaps assigning via proxy objects. I used the plug to assign Vmap to the Room and tried to manage it via Vmaps in Layout... not perfect, mostly because of brute-linear interpolation of Vmaps in LW.
I think a Shader like the one above would be the solution for two reasons: Vmap would not have to be applied exlusively on rendered obj's pts (it'applied to "cage" pts), which thing give much more freedom and control, and it could make a better (spline) interpolation.
I'm trying a Vmap-way to faked GI but Weighter seems to get only close, and manually applying Vmaps is not so convenient. Maybe we could make a quick radiosity pass and burn it into a VMap ? Surely i've not exlored all the possibilities.
In "extreme" situations i take a shot of (i.e) roof's wire in modeler, than i paint light in photoshop and apply it as diffuse map.
You thechnique is awesome, very paint-oriented and with very short render times, but how does it deal with non-square rooms, curved walls or other complex situations ? Input params in gradients are not so comprehensive, in some cases i found myself trickin' without an effective solution. Just hoping Newtek add a "spline-offset" input type, so we can control falloff along curves, and a "custom obj" one, so gradients could keep its value in the entire obj area, and then decay around that.
Again, i hope that the fantastic "Ambient Occlusion" shader will be able to deal with textures AND with Vmaps. I.e, a wall in a room can be darker on the top, while AmbOcc effect should be very dim in the low part, near the floor. If it can access Vmaps, also Color Vmaps could be used for bleeding..
just dreaming

Regards,
Paolo Zambrini
 
  10 October 2004
Yes with a cage points it would work well, but still I don't know if is easier to use many points controlling the interpolation or to use very few points and to adjust the interpolation with the parameters of the own gradient.
The advantage of working with the Input_Parameters based on distance of the object points or in our specific case with Nulls, is that we can adjust the values of each gradient independently; for example in a curved wall (as the case that you mention), let us suppose that this wall is white and is in front of a cyan wall (front view), we can use a gradient with input_parameter based on X_distance_to_object and to adjust the gradient with only one Null so that the extreme of the white wall are tinted with cyan and the concave part remains white (doesn't care how many curves has the wall). In more complex cases we can use several Nulls (distance_to_object for each Null) or if we use Medium antialiasing we can only use one Null that moves along the walls in every frame(post behavior repeat), with MB activated the effect is even better than if we used several Nulls or points.



Gerardo
 
  10 October 2004
Originally Posted by gerardo: In more complex cases we can use several Nulls (distance_to_object for each Null) or if we use Medium antialiasing we can only use one Null that moves along the walls in every frame(post behavior repeat), with MB activated the effect is even better than if we used several Nulls or points.

Gerardo


Effectively i hadnt thought about using Motion BLur, great deal.
I've a simple example but still canot attach files (i remade my CGT account recently) so i cant give you an example where i think Vmaps can help mopre than nulls.
Surely best effect is obtained with a combination of the two, but since you're the "true gradient guy" i'm curious to understand how would you threat a case like this
I'll post it as soon as possibile

Paolo
 
  10 October 2004
isn't that I think that everything should be made exclusively with Nulls (or gradients); up to where I understand, if multiple Vmaps is used for each specific area, would be possible to adjust them independently; but if was used only one Vmap for everything, any adjustment would be applied equally to all the areas, what doesn't make it very versatile (I'm imagining this as if they were weightmaps).
Paolo, would be interesting to see your example, perhaps there is something that I am not taking into account.



Gerardo
 
  10 October 2004
Oh, quite a simple one, but i still cannot attach files ;(
Think about a room with a curved roof, i.e a waved one (in section). Meeting of a wall and roof defines a curve, not a line (i hope i'm understandable). This way you cannot use a null to control color bleeding, but you've to use several ones. Maybe animated null + MB is the key, but i thought Vmaps could help there.
Another last-minute solution is using morphing; model a squared room, manage bleeding with a Null, then morph the room into final one with MorphMixer and bleeding will follow the curve.
...or not ? Will bleeding remain the same ? Does Gradient behave like it's always in Global Coord mode, so bleeding will remain linear ? Gonna make some tries.

Paolo Zambrini
 
  10 October 2004
Sorry for delay, I made some simple tests with your example (curved roof) and you don't need many nulls; only 2, one for X and the other for Y. Everything the rest is in how you adjust the gradient parameters



Gerardo
 
  10 October 2004
Can you post a screenshot ? Just curious

Bye
Paolo
 
  10 October 2004
The first image is with 2 nulls, the second just with 1
Im refer to the ceiling, of course


Gerardo
Attached Images
File Type: gif curveceiling1.gif (20.9 KB, 219 views)
File Type: jpg curveceiling.jpg (80.6 KB, 288 views)
 
  10 October 2004
Love the soft look!
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  10 October 2004
Ok, there it works
It was not what i had in mind, i wonder why i still cannot attach images...
Anyway, i tought about a more complex room, with a section like this (think at the roof like a smooth spline):
_________
_____ / |
_____/ \____/ |
/ |
/ |
|___________________________|

Now, lets suppose the roof is red and all the walls are white. You have to simulate Red bleeding on the walls, following that curve. Using Y or X distance from nulls can be quite tedious, since you've to set up a lot of gradients. Maybe here you can use that trick you talked about: using just one null, animated along Roof's curve, and Motion Blur.
Anyway, in certain situations common Gradient's input params are not enough
That's why i hope and ask NT adds a "distance to curve" one, or a "normal falloff" one (in this case, the gradient would analyze roof's geometry and make the effect decay along its normals).

Bye
Paolo Zambrini
 
  10 October 2004
Originally Posted by PaZ: _________
_____ / |
_____/ \____/ |
/ |
/ |
|___________________________|

Bye
Paolo Zambrini

OH MY GOD.
My wonderful sketch is totally messed up
Ok, i'll wait till i can attach something... i apologize.

Paolo Zambrini
 
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