more on alpha problem

[roseman]

I composed this letter as I thrashed about. 

Note at the end I did manage to get some manner of work around.
********

Continuing from the previous message

I tried to directly set alpha with:

awk '{if($10 ==1) print $1, $ 2, $3, $4, $5, $6, $7, $8, $9, "  .1";else print $0 }'  
intersection.off>intersectionalpha.handmade.off

I then brought up intersectionalpha.handmade.off in geomview (it was valid but no  
transparency evident) then I saved this to a rib file.  called it intersection3.  This looked the  
same as intersection.  In fact: a diff on the two files shows no significant difference
So somehow my handmade change has been lost.  :

descartes 123% diff intersection intersection3
2c2
< Display "intersection.tiff" "file" "rgb" 

---
> Display "intersection3.tiff" "file" "rgb" 

55a56,61
> TransformBegin
> ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

> TransformBegin
> ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

> TransformBegin
> ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

66,69d71
< ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

< TransformBegin
< ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

< TransformBegin
19114,19122d19115
< # push appearance
< AttributeBegin
< 

< # Interpreting Material **********************************************
< ShadingInterpolation "constant" 

< Surface "plastic" "Ka" 0.3 "Kd" 1 "Ks" 0.3 "specularcolor" [1 1 1] "roughness" 0.0666667 

< TransformBegin
< Identity
< TransformEnd
19126,19128c19119,19120
< TransformEnd
< # pop appearance
< AttributeEnd
---
> TransformBegin
> ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

19139,19142d19130
< ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

< TransformBegin
< ConcatTransform [1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 

< TransformBegin
143576a143565,143567
> # pop appearance
> AttributeEnd
> TransformEnd
143590,143591d143580
< # pop appearance
< AttributeEnd
descartes 124%

&&&&&&&

so I tried a frontal attack on the rib files themselves--I tried:

descartes 124% grep -n Opacity intersection
2608:Opacity [1 1 1] 

39892:Opacity [1 1 1] 

and changed these to 

descartes 124% grep -n Opacity intersection
Opacity [0.1 0.1 0.1]

This changed the appearence of the edges of the resultilng tiffs (made them less opaque)  
but left the surface unchanged. 


next I tried adding in (in two places) 

# Interpreting Material **********************************************
Opacity[0.1 0.1 0.1]

This seems to do it! 

Needs some tweaking.  Anyhow that's what geomview needs to write.