[vtkusers] Latest on lights

[James C. Robinson]

Dear All,

I have had some comments (thanks Nigel & John) but nothing that has solved
the problem. However, I have discovered some interesting/important
facts/phenomena that may shed some light (oh - there I go again).

Firstly, the elevation and azimuth: After some experimentation, it
transpires that an azimuth of 0 is actually looking back in along the Y
axis. This is very important. It may be stated somewhere in the
documentation but not in any place obvious and certainly not where it should
be (as part of the explanation of vtkLight:: SetDirectionAngle). Next, I
have also discovered that the headlight obscures the light from other
lights. I attach (I'm not sure of you will receive it, but e-mail me of you
want to see) a doc containing two images. Firstly, showing the mesh from an
angle with both the headlight and the second (key light) turned on. The next
image is from the same angle, but this time the headlight is off. Incredibly
(to me at least) the surface being lit by the second (camera) light is
brighter?? Any ideas what is happening here???????

Again, in hope.

Jim

______________________

James C. Robinson, PhD,
Chartered Engineer,
Kepler Engineering Software Ltd.,
42 Rivergrove, 
Glanmire, Co. Cork,
Eire

Tel:         +353-21-4822028
Tel:         +353-87-2393010
Fax:        +353-21-4822721
E-mail:     j.robinson at kepler.ie
______________________

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