[Bf-committers] DOF camera parameters.
Thu, 10 Jun 2004 17:33:32 +1000
I considered posting this to the functionality board, but since it's
code I've already written, I thought I'd post it to bf-committers... :-)
As part of the Aqsis RenderMan exporter that I've been hard at work on
over the last two weeks, I've added some new parameters to the Blender
1. Focal length ("internal" camera parameter).
2. Focal distance (distance to point of perfect focus).
3. f-stop (traditional photographic measure of the aperture size).
These parameters truly "belong" to the camera, rather than to the scene
or exporter settings. This is because it makes sense for different
cameras to have different settings, and for the settings to be animated
with the camera itself.
In the Aqsis CVS version of Tuhopuu, these camera parameters are
completely finished, hooked up to IPOs, etc. Here's a screenshot
showing them in action:
Given that it's all set up for people to play with, I have a few
questions. These are probably best answered by those who are the true
"custodians" of Blender (probably most of whom are active on this list):
1. Are there any changes I should make?
2. I'd like to display focal distance (the distance to the point of
perfect focus) in the scene. Currently, I do this with a simple cross
along a line from the camera, which is displayed when "ShowLimits" is
selected. Should this display be improved? Should it perhaps include
some indication of the depth of field: ie, some kind of "in focus
range", over which the focal blur is always within some arbitrary
value? Any ideas (or mockups) for how this should look?
Q: Why do we need "FocalLen" when "Lens" apparently contains the same
A: Lens in Blender controls the angular field-of-view of the camera,
whereas FocalLen is the camera focal length expressed in Blender scene
units. The alternative to this scheme would be to use the Lens setting
in combination with a less-intuitive scale factor to find the focal
length in scene units. I thought it was best to separate these two so
that the settings were available in the most straightforward fashion.