[Bf-committers] Duplification of Objects while Ray-Rendering

[Ton Roosendaal]

Hi,

This would have worked better with just a .blend example.

For raytraced glass to work proper, it needs real volumes (manifold  
meshes). Refraction needs an entry point and exit point for good glass  
simulation. The entry point normal typically points opposite to the ray  
direction, the exit point has a normal in the same direction as ray.  
For this reason ray_transp faces take not part in double sided  
rendering.

But, I have no idea what you did below... for me the 'outline' of a  
glass follows the entire surface of the glass, as if you cut a slice  
from it. That should work fine.

-Ton-


On Friday, Jan 23, 2004, at 06:22 Europe/Amsterdam, Meino Christian  
Cramer wrote:

> Hi,
>
>  Effect:
>  =======
>  After RAY-rendering a wineglass, it appears somehow "doubled" on the
>  scene (...I said nothing against a doubled portion of a good wine
>  here :)
>
>  Do as follows:
>  ==============
>
>    * Start with the default scheme
>
>    * Create a curve according to the outline of a wineglass
>
>    * Convert it to mesh
>
>    * Spin along the rotation axis of a wine glass
>
>    * Remove double vertices at the start- and endpoint of the rotation
>      ("...where bertices meet..." :)
>
>    * Go to EDIT mode select all vertices and FLIP NORMALS OUTSIDE
>
>    * Assign material with ray transparency (IOR=1.54), some phong
>      shading, specular reflactions and such as you like.
>
>    * Render with RAY set
>
>    * TADA! You will get two glasses ... one inside the other.
> 	 (hicks! .... or may be a had two much wine...seeing everything
> 	 doubled ?)
>
>    May be this can be cirumvented by building a "solid" glass from a
>    closed curve...BUT:
>
>    1.) If an enduser previously had used a blender with no RAY
>        rendering support and has done the wineglass-examples from the
>        2.0-Blender-Manual -- s/he will expect to do/see the same only
>        more realistic now, since RAY is enabled.
>
> 	   This """hurts""" (watch those many "'s!) the
> 	   "Principle of least surprise".
>
>    2.) More a feature request than a beetle-report:
> 	   Would it be possible to make "double sided" work for
> 	   RAY rendering also?
>
> 	   Makeing complex shapes from closed curves --  especially if you
> 	   have build the shape with an open curve before and tries to
> 	   close the curve (see 1.) ) -- is a real pain...
>
>
>  Keep rendering! :O)
>  Meino (mcc)
>
>
>
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------------------------------------------------------------------------ 
--
Ton Roosendaal  Blender Foundation ton@blender.org  
http://www.blender.org