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skyPhyr
03-11-2002, 10:54 AM
Hi Guys,

Just thought I'd throw a few quick questions in here.

Lighting - the light that's in the explorer by default - what effect does it have on the scene?? should I delete it?

The fresnel effect - what node should I use in the render tree for that?? I used facing ratio in maya...

And the last one is modelling related not rendering and lighting sorry - just saving putting posts everywhere :-)

In maya when I wanted to create lines with sharp corners I would create a cubic EP curve finish it then start another one snapping it's first point to the end of the previous one. I've done all that with no problem in XSI - just what do I do to attach the two curves making them one?

thanks for any help,

skyPhyr.

wlau
03-11-2002, 12:36 PM
Heya Skyphyr,

1. Lighting Question:

The default scene light is a white infinity light with a 0.75 intensity. It is automatically hidden in the scene, but once you delete it from explorer, you will have no lighting until you create another light. When you are buliding a new scene it is recommended that you just delete this light and establish your own lighting setup.

Just in case you don't know how, hit the -scene- button and left click on light and just hit delete.


2. Fresnel Effect:

The fresnel effect can be achieved in XSI by creating an 'incidence' node in the render tree.

You can find the incidence node under 'Nodes --> Illumination --> Incidence(s)'.

After you've created the node, the basic setup would be to connect that to your surface shader's (phong, blinn, etc) diffuse, ambient, and transparency inputs.

In case you are not using XSI 2.0, you must create a scaler2color conversion node (nodes --> conversion --> scaler to color). From there, just connect that node to the surface shader. With XSI 2.0, it will automatically create that conversion node whenever necessary, so it's much easier.

A tip for creating the fresnel effect is to add a 'colour-correction' node (nodes --> image processing). This node enhances the fresnel effect by allowing you to control the hue\contrast\gamma etc... of the incidence data that you connect to it.

Anyways, the tree would like this:

Incidence --> Scalar2Color --> Colour Correction (if you want) --> Phong (diffuse,ambient,transparency)--> Material Node.


3. Curve Question:

Okay I'm not sure if I understood correctly, but here's a go. When you have two seperate curves (whatever type they may be), goto the model panel (1) and go (Create --> Curve --> Merge) It then asks you to select curve boundaries. So say select the end point on the first curve (just highlight over the whereabouts of the point) and then highlight the first point of your second curve and it will automatically join them up together as a single curve.

What's neat with the merge function is that it allows you full control in how the blending works between the two curves. You can adjust it in the merge properties panel that pops up.

After that's done, just select the merged single curve and hit freeze (bottom right panel under EDIT) and you're free to delete the two seperate curves!


Anyways, I hope that helps ya out =) If anyone has any corrections to be made, pleaes do so.

wlau

skyPhyr
03-11-2002, 01:45 PM
Thanks - that was all really useful.

I've got another quick question or two if that's ok :-)

The lighting displayed in my viewport is completely different from the lighting in my renders..

Is this usual? It looks as though the lighting in the viewport doesn't allow for the falloff..

Also when I'm using gi etc I get alot of light gathered in the corners where objects meet.... how do I fix this? I had this same problem in maya using mental ray to render, but after I went and changed my lights to have quadratic falloff and set the intensity up correctly it was rectified..

Also is there any shortcut to center the center of an object/selection - particularly when translating etc using global axis..

Thanks again for all the help,

skyPhyr

wlau
03-11-2002, 03:33 PM
Skyphyr,

For lighting, the viewports have done a pretty accurate job of showing the light sources and their falloffs.

However, I use the render region tool practically religiously during the lighting\texturing phase. So any inaccuracy I may experience in the viewports is pretty much negated since r.region is on the whole time =)

Global Illumination - Sorry, I really can't help you there. I haven't touched into that aspect really whatsoever. I hope someone else will be able to account for this. But It seems to me that you found a nice workaround for it.

Regarding the last question, when you say to center the center of a selection or object, are you wanting it to move to the scene's origin (0,0,0) or to the object or selection's own center?

Generally with the way I model, whenever I need to adjust the center of an object, I just click 'Center' up in the right hand corner and move the center to anywhere I want.

I looked around for custom scripts just now, but had no luck on finding anything.

One other thing, you probably know this and aren't even asking for it, but when you do select say five faces, you cannot alter the center of that selection (can't change the location at all). By center I mean the pivot point for say a rotation of those faces.

Sorry if things aren't too clear here. I'm still trying to figure out XSI fully =)


wlau

wlau
03-11-2002, 03:38 PM
Oh btw - when I was talking about altering the center's location of an object by hitting the 'center' button, the equivalent to that in Maya would just be hitting 'insert'.

wlau

skyPhyr
03-11-2002, 03:45 PM
hmmmm... ok - mine comes up bright white in the viewport, but renders quite dark...

yeah - I was talking about moving the center of a selection of a number of components (faces, points whatever). I've found where to change it to global to move it, but can't find a way to automatically place the center (equivalent of origin in maya - accessed through insert) in the center of the selection..

thanks again,

skyPhyr

skyPhyr
03-11-2002, 03:56 PM
oh and forgot to mention - the solution I used in maya didn't work in XSI for the gathering of light in the corners if anyone has some suggestions :-)

cheers,

skyPhyr

wlau
03-11-2002, 03:59 PM
Bright white? Is this coming from the default infinity scene light ? Or is a custom lighting setup?

Hrm, whenever I'm working in local mode, whatever selection of elements (face,vertices,edges) I select, it always translates\rotates\scales from the center of that selection.

When you work in global mode, it always acts as if it were around the origin.

Maybe posting a picture would help?

wlau

skyPhyr
03-11-2002, 05:08 PM
I played with the viewport lighting settings and the viewport preview is exactly the same as if there was no light decay at
all.

Here's a screenshot of the viewport when it's supposed to have a light decaying..

thanks,

skyPhyr.

skyPhyr
03-11-2002, 05:15 PM
ok - and now I've gone to make the screenshot showing the picture of the scaling going not going to the center of the selection and I found a little "COG" center of geometry button that put the pivot point right in the middle of the selection :-)

so problem solved for that one :-)

ambassador
03-12-2002, 12:18 AM
Heres a question,


How do you export a model to a format other than XSI's, like OBJ, LWO, or 3ds?

Cyberdodel
03-12-2002, 02:57 AM
Does anyone know how I can use normal objects with their povits like bones without making each object, that is supposed to be a bone, child of a bone ?

Don't understand ? I mean s.th. like IK in 3D MAX. For example for robots. There you can just parent some objects and switch on IK. Now you can animate technical objects without bones, by moving the end (effector). You can just set rotation limits for each object.

It would also be a help, if anyone tells me, that it's definitly impsossible in XSI.

Other questen: In 3D MAX you can use boolean operations an splines, is that possible in XSI too ? Or do I have to use Illustrator for complex curves/splines ? I miss some features from MAX on the one hand on the other hand I enjoy the new features...

By the way, excuse my bad English :D

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