Fast skin misss and override [solved]

[Nizar]

Finaly I take my fingers on The art of XSI book (thanks magog )
The book is a series of image, with a little (too little IMO) comment below. The tutorials (three in total, one generic and touch many XSI parts (a mantis) and other more specifics).

In Mantis tutorial I find a problem in rendering section. Author create a override for the material, in one partition. In this override he had only the Material_Material parameter, selected from base material properties. After this, in render tree, he add a SSS Fast Skin and connect to override node. Now, in Softimage 2011 (and I controlled 2012 and is the some) there is no more this material, but a Find the Fast Skin (misss). The problem is I cannot connect Fast Skin (misss) node with Override node. I tried many time, adding different parameters to my override node (all parameters), but no one match with Fast Skin (misss) output, this node a different output color (brown) and cannot connect with any input in my override node. The strange thing is I can connect Fast Skin (misss) with a normal material node, he connect to MATERIAL input, but if I override material input parameter don't work ( had a different name MATERIAL-MATERIAL and different colour ( a dark brown).

Any help about?

[Hirazi Blue]

I can confirm something has changed in this respect.
I think you'd have to use the "misss_fast_shader_x"
to use in a pass to get similar results...
;)

[Nizar]

Thanks very much Hirazi for your time. But no, msss_fast_shader_X must be connect to surface, and not material, and, in any case, the material look really different from fast skin misss

Learn Mental ray is frustrating experience

[Hirazi Blue]

I think you might be mistaken. When I set up a material in my default pass using a unaltered Fast_Simple (misss), like the book tells me to, the result seems the same as using the unaltered misss_fast_shader_x in the override of a pass...

[Nizar]

I don't think this is my error, I try with example file in CD, and result is the some:

This how must be the Fast Skin Misss (can connect without problem at material node)
and this is result of misss_fast_shader_x


It is quite different. Note cannot connect to Override Material-Material, but must connect to another imput surface (and, in any case, result is quite different)

[Nizar]

And if I open the final mantis file, there is no track about Override... So override is now limited and cannot use some nodes? I don't find nothing about in F1 guide.

where can I find a updated and valid guide to rending in softiamge mental ray? For me is a real issue, for every caged aspect/feature and for every bug I lost hours in experimenting...

[Hirazi Blue]

You misunderstood me earlier (I should have made it clearer!).
In a simple test setting, I created a sphere and tested
if the unaltered ("out of the box", no values changed) "Fast_Simple (misss)"
gave me the same result as an unaltered
("out of the box", no values changed) "misss_fast_shader_x" in an override
(overriding the surface value).
In that specific test case there seemed to be no difference
(between two renders).

The fact that the mantis shader looks differently obviously stems
partly from the fact that there are probably numerous values changed
and some additional textures (if I recall correctly) in the Mantis shader.
I will try to find the disc accompanying "the Art of XSI" book
and will look into it some more...
No promises (I have to find the disc first)
;)

[Nizar]

Hi Hirazi, thanks again for your time
No, there is no texture in either tests (and in my personal work). In any case, override don't seem work properly.

[Hirazi Blue]

Okay, I've reached the limit of my understanding of overrides. I can however offer you a workaround. You can assign materials to partitions. In the case of "Mantis_final" on the "Art of XSI" disc, you can exchange the "Material5" locked material like so:

Select the "override" in the Explorer
Go to the RenderTree and Refresh > Copy the whole shader branch (everything except the override itself)
Create a new material in the Material Manager > add the copied shader branch to the material
Delete the original override in the Explorer...
Select the partition (the partition itself - for instance "Mantis" in the "Mantis_Color" pass).
Assign the material to the selection.

When creating the material anew, you can obviously skip the steps about the original override.
The new material isn't locked to the override (as it isn't created by one), accepts SSS and is only assigned to the members of that one partition...

Hope this finally helps a little (I've given up... )
;)

[Nizar]

Hi Hirazi,
again, thanks for your time, If you travel in my country I will be happy to offer you a beer . Unfortunately don't work. In this way I cage the material partition, but cage the material in every (i.e. mantis color partition) pass partition, and the new material will be the some for Color pass and Specular pass. In the tutorial, override is applied to a single partition in a specific pass.

It is very strange. I can live without override, but cannot understood why don't work. Reading SI wiki, I find the different material and his explain: Fast Simple Misss is a phenomenon node (brown), and can be connected to material Input; the problem is override node, when assign material at override, it become Material-Material, and has an input custom (a dark colour dot).

why it don't work: is a bug, like volumic in physical sky, or is it my error? Cannot find nothing about...

[Hirazi Blue]

First up: never trust the WIKI completely, it is in parts quite outdated...
I must think about what you wrote about the partition problem some more. It is my understanding that you can place a material on every separate partition (i.e. "to a single partition in a specific pass"), but you must obviously do so, while the specific pass is active and not merely attempt so in the explorer while another pass is active. I placed a material on the Mantis partition in the "Mantis_Color" Pass while it was the active pass. Maybe that's the difference. (Or maybe I am just misunderstanding what you're trying to say. If so, please say so)
The strange thing is, I haven't found any explanation for this original problem anywhere either. My feeling is, that Softimage wants to change the basic material override workflow (resulting in "ugly" locked materials created by all the overrides) to the probably more "clean" method of materials on partitions. But that's merely guesswork. And it's still strange I can't find any helpful info about this. And believe me, I've tried to find it also...
;)

edit: just thought of something: are you perhaps applying the material to the pass instead of the partition within the pass?

[Nizar]

Hi Hirazi and again thanks and sorry for my late reply, I try different solution, but have not result.
I apply materials to partition, cannot apply material to pass. And as I wrote, when I apply material to one partition (i.e. mantis) in one pass (i.e. color pass, the active pass), all some partition in other pass (i.e. the specular pass, not active) receive the some material. If you can assign a different material to partitions in different pass, I think there is something wrong in my scene...

[Maximus]

I really cant understand what is the problem, can you illustrate further so i can try to help?
You cant assign materials to Passes, a pass is a container of one or more Partition, you can apply shaders to partitions.
So when you create a new pass, it creates a default background_objects_partition with all the objects in scene (except lights) into this partition.

Now you can assign a shader to this partition, but if for example in this partition you have 5 objects and you want to assign different shaders to each object you need to select the object and create a new partition and assign the shader only to that partition.

You can also have 2 different objects, in one single partition, with 2 different materials, without using overrides.
Basically i dont get what you are trying to achieve, what do you need to do?

[Hirazi Blue]

@Nizar - Are you sure you're applying the material to the partition, not just to the object in the partition?
Select the partition node (the "name of the partition") and then in the Material Manager use "Assign Material to Selected Objects". That way, the material is specifically applied to the partition. The object inherits this material but only in that partition...
;)

[Nizar]

@Nizar - Are you sure you're applying the material to the partition, not just to the object in the partition?
Select the partition node (the "name of the partition") and then in the Material Manager use "Assign Material to Selected Objects". That way, the material is specifically applied to the partition. The object inherits this material but only in that partition...

I doing so:
before assign a new material


after, as you can see either partition has the new material assigned


This is my scene, but is the some with I use the tutorial example scene.

Maximus@ I send to you a PM.

[Hirazi Blue]

I think that your problem has something to do with the way the Explorer works.
The materials that show up in the Explorer are always the ones of the active pass. For example: in the following pictures you see screenshots of the Explorer: when the pass named "Pass" is active, in this pass I applied a material called "Phong_Preset2" to "sphere1" in the partition named "Partition"...

pass.jpg

The second picture shows the same situation when "Pass1" is active, and to its "Partition" I applied a material named "Material1"

pass1.jpg

As I hope you can see, the Explorer shows the "wrong" material for the non-active passes...
That's probably why its best to set the Explorer scope to Active Pass and not to Passes...
;)