[Bf-committers] Drop to ground mod idea

[Campbell Barton]

On Tue, Dec 13, 2011 at 7:24 PM, Knapp <magick.crow at gmail.com> wrote:
> I keep finding cases were I need a stack modifier that drops something
> to the ground.
> Examples of this are:
>
> A big group of trees that are in the dirt but the dirt is done with a
> cloud texture into a displacement mod. Getting each tree to the right
> place is a real pain. Then you adjust the cloud text and have to do it
> all over again.
>
> A boat on dynamic or ocean sim water. How do you get it to float with
> the waves in an animation? With ocean sim you don't even have an
> animated mesh to parent to. Being able to drop a vert to the water
> surface would be great. In the case of a big ship you might even want
> to drop 4 points on the ship to the water surface and not just a point
> of the surface but an average of the surface in an area under the
> boat.
>
> A car driving over rough ground in a film. Also a real pain to do but
> a drop to mesh surface would be great! Perhaps for each wheel.
>
> Mod options:
> to surface or plane or coordinate like +100 X.
> Surface as defined by a vert, surface point or an averaged area
> Direction (a vector?) to fall.
> Depth of penetration into surface.
> What is doing the touching, IE a point from the object or an offset
> from origin or the lowest surface etc.
> Perhaps some way to make the 4 points of a car that touch change the
> rotation of the object with possible locking of axis (plural form?).
>
> Possible problems is that it is heading into the direction of physics
> and might need more data, for example over time, than is easy to
> implement. Even with these limits I would find it useful even as a
> simple drop to point along an axis but much better as drop to surface.
>
> I am sure something like this must exist for the BGE but I want it for
> film and still picture making.
>
> I found this script.
> http://wiki.blender.org/index.php/Extensions:2.5/Py/Scripts/Object/Drop_to_ground
>
> Is there anything else that I might have missed or another way to do this?
>
> --
> Douglas E Knapp

Hi, firstly I think we should have at least 1 tool for simple drop to
group functionality (with some options for offset and orient to the
grounds shape).

Further this gets a bit tricky because there is not one right way to
solve the problem, with how the tool functions (do you try to
intersect the base of the object with the grounds surface for
example), implementation too - could use objects/duplis/particles etc.


As for animation, for this I think a separate tool is needed since for
animation you get too many variables/issues
* how to follow surface without jittering, to follow surface over one
point or 4+ points on each corner of the object,
* some option to smooth out motion or dampen it
* a useful way to change speed
* how to manage multiple objects (possibly even have them not run into
eachother)
* you may want other objects to match this speed - like wheels of a
vehicle turning.

If a developer doesn't have an immediate use case its a bit arbitrary
as to which issues you try to solve and how much detail you go into.

-- 
- Campbell