[Bf-committers] CAD/Robotics extensions to Blender (Was Re: CVS commit: editobject.c)

[Douglas Toltzman]

I don't speak for Ton, or the Blender Foundation, but this sounds like a
good candidate for a code split.  I'd love to have and use a CAD-like
version of Blender, but I cannot see a blending of the current Blender
paradigm and features with a mechanical modeling tool.  The user interface
would become cluttered and the application would probably become bloated.
I don't believe you can be all things to all people and still perform any
one function really well.

Although I'd vote for a separate source tree for the CAD modeler, I'd ask
that the file format remain compatible between the two so one could model
different parts of the same project in the modeler that best suited the
part being modeled.

Just my thoughts.

Douglas Toltzman
Hubert, NC

On Tue, 27 Jul 2004, Herman Bruyninckx wrote:

> On Tue, 27 Jul 2004, Ton Roosendaal wrote:
> 
> [...]
> > One of these design concepts was to always try to provide a non-exact, 
> > interactive & visual toolset. No axis-awareness (x-axis, y, z), no coordinate 
> > awareness (typing in location/size/rot for adding object), and no scale 
> > awareness (we have the "blender unit").
> >
> > That's giving a nice focus for designing features (and I'm the first to admit 
> > many things in Blender don't do well still). But it's not an axioma; when 
> > exact editing is needed (like exact rotation around exact location) you 
> > should have the tools to do so. But it's secondary, and not primary like in 
> > most CAD tools.
> 
> So, what should I conclude as someone who is mainly interested in
> Blender for its "CAD potential" and "exactness"? Will additions to
> Blender that focus on the points you mentioned above (realistic
> measures, axis-awareness, etc.) have a chance to be accepted? And yes,
> under what conditions?
> 
> To be a bit more concrete: I am interested in developing additions to
> Blender that make it into a powerful 3D visualisation and CAD tool for
> robotics and machine tools. Roughly, the missing features of Blender in
> this context are:
> - creation of "mechanical" devices, which has traditionally a somewhat
>    different user interface than animation and games.
> - addition of kinematics routines for "robot like" devices, which are
>    not like the animation armatures that have only spherical joints, but
>    are mostly built from revolute and prismatic joints. The kinematics for
>    this kind of structures can be made _much_ more efficient than the
>    current IK of Blender. Also if natural dynamics are included.
>    (And no, the ODE way of doing things is _not_ optimal for robot-like
>    kinematic structures. But it is nicely complementary.)
> - addition of physical properties to parts, especially inertia.
> - addition of the IK of mechanical structures with closed chains,
>    including the code to close the chains during "assembly" of the
>    structures.
> - addition of IPOs that are common in robotics, e.g., for redundant
>    systems, with so-called "trapezoidal acceleration profiles" etc
> 
> We just started working on this "project" with an eye on integration in
> Blender. I have now a student working on using Blender to visualise
> robot motions that are fed to Blender from a real robot (via a Python
> script, and a CORBA EventChannel). I hope to get some real robot systems
> animated in a month or so.
> 
> We have most of the mentioned kinematics algorithms in one form or
> another, but the effort to bring them into Blender in a way that can
> serve the long-term goals I have outlined above (_and_ that is optimally
> useful for other Blender users too!) is still substantial. So, don't
> hold your breath :-)
> 
> [...]
> > And for myself, yes I reserve the right to veto out stuff. Won't do that 
> > easily, but definitely on obscure additions. And always after feedback of the 
> > other project admins.
> I respect this policy! But it would be nice to get an idea about the
> "veto proneness" of the "robotics additions"  I suggested above.
> If you think they are of really secondary importance, than I'd better
> start looking elsewhere :-)
> 
> Herman Bruyninckx
> http://www.orocos.org
> 
> -- 
>    K.U.Leuven, Mechanical Engineering, Robotics Research Group
> <http://people.mech.kuleuven.ac.be/~bruyninc> Tel: +32 16 322480