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MJV
12-11-2004, 11:10 PM
Is there a node somewhere that offers more control over specular than the pitiful control offered in the phone illumination node? Something with falloff controls allowing me to edit the shape of the falloff curve? Or do I have to build some humongously big render tree to achieve this basic editing function?

JDex
12-11-2004, 11:16 PM
MJ... why is everything so negative? Pitifull? It seems not so to most. Never said to myself... gee I have no specular control.

Maybe plug a gradient, or exponential node in to the specular input...

Honestly, when you ask a question like this... I just start thinking to myself... if it is such an aweful app, why does he use it?

MJV
12-11-2004, 11:35 PM
No need to get all reactive JDex.

Ablefish
12-12-2004, 10:30 PM
Sorry MJV, but I'd have to agree with JDex on this one. While I totally understand the frustrations of moving from one package to another, it might just be better if you take that one deep breath before posting a question. There are a lot of people that are very willing to help, but it's tougher when the tone is constantly negative.

Some people think the nodes in the Rendertree are too lean, and others say they're too bloated (how often do you use Translucency or Incandescence, for example?). My biggest criticism with most of the nodes is the parameter names - they're not usually very intuitive unless you've been writing shaders or studying light behaviour. Still, it does get better over time when you realize how much control you really have by using one or two additional nodes.

Atyss
12-15-2004, 05:17 AM
>>> Is there a node somewhere that offers more control over specular than the pitiful control offered in the phone illumination node?

There are other shaders you can use, Phong is just one of them.


>>> Something with falloff controls allowing me to edit the shape of the falloff curve?

No. Unfortunately the curve widget (the one from the proportional ppg for instance) is not available in any shaders (and I don't think it's possible). You should need to mess with a post solution.

If you really want to split your specular from the object, you can use a lambert and plug it into the base_color of a Mix_2colors. Then plug any illumination shader of your liking in the color1 input of that same Mix_2colors. Set the weight color to white, and set the mode to Add. Finally, in the illumination shader connected in the color1 input, disable the diffuse, or set it to black. Now connect anything you want in the specular input. There is not much interest of doing this beside having 100% seperate controls though.


>>> Or do I have to build some humongously big render tree to achieve this basic editing function?

I think you are looking for some ala 3ds max's Multi-Layer material, aren't you? There is not such thing available in XSI.


Btw, if you're unhappy with the factory shader, email Softimage so they may upgrade them, or learn to write your own.


Cheers
Bernard

MJV
12-15-2004, 06:42 AM
Brilliant Bernard. That is pretty close to the solution I arrived at myself after Jdex pointed me to the gradient node. I did as you said with the addition of a gradient node inbetween for further control. Now I have to admit that there is a good level of control there, and the gradient actually opens up a lot of options for nice pearlescence effects. I'd still like to see a more straightforward method with some graphic feedback approximating the curve. I have to admit I was surprised to find that Mental Ray nodes are so spartan. I can see the beauty of it to some degree for sure, but I feel it's very restrictive at the same time, that they could be much more than they are now.

@ JDex and Ablefish: Ok, I'll try to be more tempered in my choice of words. I think you guys are confusing impatience with negativity. I don't feel I'm a negative person, just impatient with my own inabilities to grasp things sometimes to the point where by the time I have to ask I'm mad at having to. If I didn't think that XSI was a good package with much to teach me I wouldn't be here.

>>> Is there a node somewhere that offers more control over specular than the pitiful control offered in the phone illumination node?

There are other shaders you can use, Phong is just one of them.


>>> Something with falloff controls allowing me to edit the shape of the falloff curve?

No. Unfortunately the curve widget (the one from the proportional ppg for instance) is not available in any shaders (and I don't think it's possible). You should need to mess with a post solution.

If you really want to split your specular from the object, you can use a lambert and plug it into the base_color of a Mix_2colors. Then plug any illumination shader of your liking in the color1 input of that same Mix_2colors. Set the weight color to white, and set the mode to Add. Finally, in the illumination shader connected in the color1 input, disable the diffuse, or set it to black. Now connect anything you want in the specular input. There is not much interest of doing this beside having 100% seperate controls though.


>>> Or do I have to build some humongously big render tree to achieve this basic editing function?

I think you are looking for some ala 3ds max's Multi-Layer material, aren't you? There is not such thing available in XSI.


Btw, if you're unhappy with the factory shader, email Softimage so they may upgrade them, or learn to write your own.


Cheers
Bernard

JDex
12-15-2004, 07:25 AM
:D

Good deal MJV... glad you're find the control you crave.

Just_David
12-15-2004, 11:35 AM
Could an incidence node with an intensity node be used to control the specular? i used this recently, but with me being new to the rendertree I guess it could be wrong.

Atyss
12-15-2004, 03:58 PM
Could an incidence node with an intensity node be used to control the specular? i used this recently, but with me being new to the rendertree I guess it could be wrong.
Yes, it can be used. So what did you try exactly?


Bernard

Just_David
12-15-2004, 04:23 PM
Atyss i used here in the Mentalray discussion thread. Have a look and you can see how I used the incidence >>intensity>>specular on the material.

I guess I wasnt happy with the default settings and wanted a high intensity specular with a soft edge. But Im pretty sure that theres much easier and better ways to achieve this than what I have done.

http://cgtalk.com/showthread.php?t=191377&page=4&pp=15

Atyss
12-15-2004, 04:36 PM
Okay I see. I think what you need to do is mess with change_range. Connect the incidence in a change_range, and connect the change_range in the specular.

In the change_range, set the old start to 0, the old end to 1.

Now you mess around with the new range values. Consider that a value of 0 is pure black and 1 is pure white. However, since you want more "intensity", you may want to remap those values beyond the 0-1 range.

For examples, you may set the new start to 0.25, and the new end to 2. This is like having a white two-times whiter than ordinary white. The result of this is that you get a "stronger" white. The process is exactly like HDRI, where the light areas are in a tone of white way beyond 1 (sometimes up to 20!), wich is why you see light spots even in the least reflective surfaces.


Cheers
Bernard

Ablefish
12-15-2004, 04:49 PM
No worries, MJV - I do understand the frustrations and impatience. To some degree I think those are normal with software in general, 3D software in particular, and worse when coming from a different package where you already know how to do things. :)

Just_David
12-15-2004, 04:55 PM
many thxs Atyss. Ill give that go. :)

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