Planting trees, plants and rocks with bullet physic : limits not working

[MarquisDeSang]

I have a deformed terrain model.

Above it I copy tons of trees, plants  and rocks objects.

Then I use bullet physic to place those elements (randomly) on the surface of the terrain.

It's working, but I would like  the falling objects to stop moving on impact and block their rotation (prevent them from rolling).

I tried to activate all the limits, all link types and bullet properties without success : everything continue moving and rotating (on the steep hills).

In Vue d'Esprit there is a drop function that does exactly that. You place above then hit the drop button.

I hope to use this technique eventually with "Force" to place/scatter objects on objects.

[Tomas Egger]

Ola Jean,

Collect a simple project showing the problem and send us, please.

thanks

tom

[MarquisDeSang]

Just open the bullet session and press the preview button in the camera 3d view.

I did not touch anything this time, so the goal is to lock translation in X and Z and lock all rotations.

So as soon as a tree touch the terrain, I would like it to stop moving.

Placing stuff with physic is a technique that I have used for a long time. Once the physic simulation is ok, I go to the last frame, create a keyframe for all trees then remove the animation flag (This part is working fine). Then I select all the threes and move them down a little so they dig themselves a little.

Planting Trees With Bullet (Lock Translate X Z and all Rotations).zip

[MarquisDeSang]

So is this possible? If not I will plant the thousands by hand.

[Tomas Egger]

Ola Jean!

We need to ask our friend Chip Pedersen.. he is the Bullet Master..

Here, I did a simple thing which doesn't fully stopped the trees, its possible, I don't remember exactly the trick with forces.

Planting Trees With Bullet 2.zip

Use the contextual menu to change values between all groups fast in the link window.

Thanks

Tom

[MarquisDeSang]

I did it! No need for "Force" or anything. The deactivation conditions must all be met at once, not only one. So the simulation will stop if the object move less than 30 unit and 90 degrees during 1 second. Voila! Of course this must be adjusted to the scene.

I learned this technique from a guy working for 3D Studio : he showed me how to place realisticaly books in a book shelves by placing books normally inside, activating the physic simulation then shaking the furniture. He then proceeded to show me how to place rocks on a terrain with the physic.

So I guess that this technique combined with "Force" can be a replacement to "Flock" plugin (in some cases).

[Tomas Egger]

Ola Jean!

Its not Flocking, you mean Instancing :)

Bullet need new flavors :)

Thanks

Tom

[MarquisDeSang]

Does the plugin "Instancing" still exist? That would be nice to be able to automatically copy/place objects over another object.

[Tomas Egger]

Ola,

Northernlights3D have Placer Deposit.

Thanks

Tom

[MarquisDeSang]

I contacted them, but for now there is no way to check it on their website until they create the new one. Maybe I'll code a random scatter replicate plugin with some along surface options and a replace particles with object plugin. I was supposed to do that some 15 years ago and it is still needed today.