IPR problems

IPR problems

Post by Reko Turj » Wed, 30 Jul 1997 04:00:00



I've made a scene with transparent, reflecting and refracting objects. What
happens in IPR is that in some frames probably refractions go completely
dark. Darkening seems wholly random and makes uglyone-frame flashes to
object. Any suggestions?

TIA

Reko Turja

 
 
 

IPR problems

Post by bigpi.. » Thu, 31 Jul 1997 04:00:00



> I've made a scene with transparent, reflecting and refracting objects. What
> happens in IPR is that in some frames probably refractions go completely
> dark. Darkening seems wholly random and makes uglyone-frame flashes to
> object. Any suggestions?

> TIA

> Reko Turja


=====================================

Reko,

Sounds like the problem is too low of a refraction setting.  As the
light ray shoots through each surface it encounters it calculates how
that surface will effect the path of the ray.  If it hits one more
surface than has been allotted for in the raytrace parameters the ray
just stops right there, and you get black.  You might need to carefully
count how many surfaces the ray passes through to get an accurate idea,
then add an extra one or two just to be safe.

You can set the number of surfaces allowed to a higher number in the
multilister->raytracing->refract limit .  Keep in mind that pushing the
number up also pushes your rendering times up, so don't allow more than
you'll actually need.  You can easily go 10-15 levels without too much
of a penalty.  Also, be sure to check Render Globals->Quality
Params->Raytrace Max Limits->Max Refractions to make sure that it is
also set high enough.

BTW, page 63 in the "Rendering in Alias" manual has an excellennt
explanation of this.

Best,

Rob

---------------------------------------------------------------------
Eye-poppin' 3D art  / Silicon Graphics / Macintosh /  Alias|Wavefront

Rob Magiera                          |               tel 801-943-3650

http://www.xmission.com/~bigpixel    |
---------------------------------------------------------------------

 
 
 

IPR problems

Post by Chuc » Wed, 06 Aug 1997 04:00:00




>I've made a scene with transparent, reflecting and refracting objects. What
>happens in IPR is that in some frames probably refractions go completely
>dark. Darkening seems wholly random and makes uglyone-frame flashes to
>object. Any suggestions?

>TIA

>Reko Turja


I've been having similar problems. I think mine have been caused by
"flagging" my objects (in the editing menu) incorrectly. Don't know if
this will help you at all.

I had some objects that I wanted to have reflection, refraction and
transparency all together. I flagged "front" and "reverse" and
"transparency" on some single-sided objects modelled in TAV 4.3.
Oddly enough, I seemed to get the best results by removing all of
those flags. Evidently IPR knows that if it is going to reflect and
refract, it's going to be transparent. It also seems to know which
sides are going to be visible, although I'm not sure how.

My problem is that I was hoping to dissolve my refracting objects in
and out of the animation but it seems that this may be impossible,
short of rendering two seperate animations (one with the fading
objects, one without) and then combining them in composer.

I have a friend using Softimage and he says he can't get refractions
to dissolve out either.

If anyone out there knows a better way of animating a
reflecting/refracting object so that it dissolves completely, I'd
really appreciate it.

Chuck

 
 
 

1. IPR problems

i've been following the shader maker tutorial and i managed to add a SL as a
 color node.  for some reason, color now does not show up in my tuning window.
 i quit out of ipr and jotted the .mat file.  everything looks normal, but
 color still wont show.

thanks in advance for any suggestions

2. I've got to get more SPAM!

3. IPR-problem ! ! !

4. Image Conversion

5. IPR!

6. cant draw bitmap in FormCreate

7. IPR Promblem!

8. Java problems on an SGI

9. ipr renderer / batch renderer

10. IPR - projecting an image

11. IPr - projecting a map

12. Questions about Maya IPR.

13. IPR