[Radiance-general] Blender

[Thomas Bleicher]

On 20.02.2006, at 21:17, Jack de Valpine wrote:

> While you guys (Thomas and Kirk) are on the topic. Would you mind
> sharing your opinions on the capabilities of Blender as a modeling
> tool and exporting to Radiance? How would you compare it to something
> like Autocad (if you have the experience).

I would not recommend Blender to people new to 3D graphics. It's
interface is and will ever be very 'unique'. Now there are good
guides available (even for download, see "Blender 2.3 Guide" at

http://www.blender.org/cms/Documentation.628.0.html

) to help you get over the first shock but Blender keeps changing
and the documentation unfortunately not or not as fast (some
features presented in the Guide are not available in the current
2.41 version or have been moved or renamed).

Compared to $$$$ software like 3D Studio MAX you see and feel that
it's a community project. Some features that could be considered
essential are not available or very limited (i.e. solid modeling).
Integration or exchange with other commercial applications (AutoCAD)
is on the basis of community maintained Python scripts.

Now, why bother with Blender?

Compared to other open source 3D apps it _is_ very powerful and
has a lot of feature: 3D editing, animation, rendering, sequence
(video) editing, game engine and others.

Blender can deal with large data sets and it has import/export
to DXF, OBJ and a lot of other formats. The support may be basic
sometimes but even commercial applications may only provide a
small subset of the DXF format.

The GUI is "dated" by todays standards but very flexible. You
can subdivide and define your layout as you like and store it
for later access (one layout for editing, one for export, etc.).

The big advantage from my point of view is the Python scripting
API. Blender makes nearly the complete OpenGL commands available
for scripts which can be used to present and display arbitrary
data to the user (like I do in the GUI toolkit/brad interface
with 3D graphs). You have to do a lot of programming to get
something suitable for complex tasks but I have done it and we
now can built on this with future Radiance export scripts.

Whenever Blender's own features are not enough you can use the
Python Standard Library and other Python modules to extend the
functionality (database access, networking, PDF output etc.).


WRT Radiance I think Blender has some features that make it
a perfect scene setup tool:

- separate entities for object instances and object data
   (data = *.rad file; instance = "!xform ..." of this file)

- hierarchical object relations
   (nested "!xform ..." commands in Radiance)

- multiple scenes in one file with shared data
   (scene "building", scene "office day", scene "office night")

- different object types for objects(mesh), camera, lamps

- DXF import, grid/object snap and numeric input for editing


Some day in the (near) future I hope to be able to:

  1) load polygon data from DXF into Blender
  2) assign materials from library to polygon objects
  3) add lamps as desired, assign luminaire data to lamps
     get lampdata (*.ies, *.ltd) from network db or local files
  4) define viewpoints and animation for walkthroughs
  5) define fields/grids for rtrace calculations
  6) set up object animation (i.e. moveable blinds)
  7) set up sky settings and animations
     based on gensky, gendaylit or HDR images
  8) set preprocess options like mkillum etc.
  9) check scene setup in rvu
10) export to manually editable Radiance scene input for
     rad, ranimate, make or our own control scripts
11) upload export to render daemon on BIG server
12) follow render process in process monitor while editing
13) load images and rtrace results for visualization/evaluation
14) combine
      * scene images (rpict or Blender)
      * scene stats (materials, number and type of lamps, etc)
      * rtrace results (table, graphs)
      * evaluation (graphs again, falsecolor, contour images)
     to project reports
15) export scene to alternate "nice picture" renderer like
     YafRay for visualization if Radiance is not enough
16) die late, health, happy and rich ;)


At least that was the plan.

Thomas