After finding the right cross section equation, (whatever it is,) revolving it seems appropriate.
No, I disagree with myself. Variable Reflectivity may be expressed as an equation???
thanks for your reply! I like to do a laser experiment with Thea Render. For the laser i
would like to use a spot light aiming at the center of the mirror. The goal should be
that the reflecting light beam from the mirror is then parallel and only the parallel
beam will be seen in the image.
I guess i will have also to adjust the light parameters, from the spotlight several
times to get the desired look.
But first i must know how to draw that simple surface mirror with it's correct
curvature angle in order to do the test. :-)
P.S. according to this Thea tutorial this for getting thicker parallel light beams.
And the author shows a picture as proof that this works. He describes also other
techniques, but i like to try out this one. I could ask also on the Thea forum,
but i don't know if there are many MoI users or if the author modeled this
in another NURBS or poly package...
Well, i would like to post this tutorial, but i'm not sure if this
is allowed, because non-registered users can't see this tutorial
and then i have to contact the author for permission, i guess. :-(
But let's forget for a moment all this laser optics stuff, how do
i have to measure or construct properly "a flat fruit bowl surface" with
a curvature angle less than 10 degrees, let's say for example 9.5 :-)
If i can do this properly i "only" must play with the light settings,
i assume, in order to get the desired result.
From the geometry of the spherical mirror, note that the focal length is half the radius of curvature:
The angle of curvature is show in the link, as ...???
I have not been able to find the definition of the "curvature angle of the mirror"
Assuming the curvature angle = angle of incidence of the parallel ray, then the 9.5 degree arc of a circle,
resulting from the rotation of a radius curve by 9.5 degrees,
would be the curve to be revolved to form the mirror.
Hi Stefan.
Impressive results.
Maybe you could elaborate what is going on?
Part of white light beam reflects, part refracts
Refracted light again reflects and refracts, to rainbow, etc.
How is the rainbow of colors achieved. Does the color spectrum reflect physics and reality? (Within the limits of rgb colors?)
Is the prism flat on all sides, or concave?
So MoI made the prism?
in order to see the light beam and the rainbow colors, volumetrics (for the scene)
and dispersion (for the prism) is enabled. Thea is one of the very few render engines
who can do this stuff and according to their slogan is physically accurate.
The prism (made in MoI) is flat on all sides and filleted at the edges. I used this form
of a prism to see how it compares to the Pink Floyd Album Cover The Dark Side of The
Moon. Maybe they used for their illustration a regular tetrahedron, rotated at a certain
angle, i don't know.
P.S. i always wanted to try this Pink Floyd Cover*, but if you download a trial of Thea Render
and check their sample scenes to download (Laser Lab) or look at their fantastic gallery, you
will see of course much better sample images, regarding this.
*I tried this with the free Lux Render years ago and Blender, but could not get the light beam
parallel, due to the lack of knowledge at this time.
I haven't followed this whole thread (Gaussian Mirror) but I suppose that the rainbow effect and the refraction
are "simulated" and not physically rendered with the unbiased engine of Thea.
I say this because for what I've tested so far, doing a simple 4k render of a scene like this
took almost 8 hours on my i7-7700K and unfortunately the Unbiased engine of Thea is not GPU bound (like the superfast Presto engine on my 1080 Ti).
But if you have tons of cores then it should be possible to render a "physically" calculated refraction rainbow :)