Hemispherical projection vs equisolid projection
I would like to confirm whether the hemispherical projection (-vth
) of Radiance in functions like rpict
has the following projection equation:
r = f * sin(theta)
, where theta
is the zenith angle between the ray and the optical axis, r
is the distance of the projection from the optical axis, and f
is the focal length?
I have this question because the following document from Radiance-online.org (https://discourse.radiance-online.org...) claims that the hemispherical projection in Radiance is the same as the equisolid projection. However, the equisolid projection has the following projection equation:
r = 2f * sin(theta/2)
, which is obviously not the same as the first projection. Is this document wrong?