### Author Topic: Newbie question re collisions  (Read 914 times)

#### TM3598

• Newbie
• Posts: 42
##### Newbie question re collisions
« on: June 19, 2015, 02:47:55 PM »
I've been a very light user of FPP (full version) and one simple question that's bugging me and which I'd love the answer to is this;

I have a mesh (say a plane), and I use that plane for creating my forest object - say grass.

I then want to put some trees on the grass, so I use the same plane, right ?

I then want to put some flowers in there as well (okay, maybe weeds !) - so again, I use that same plane ? Right ?

Now, in my experience and knowledge of FPP;

1)  doing it as I've described above, using that same plane, if/when I want to do transforms/rotates/scales, these are done globally for all of that geometry on that single plane and that wouldn't be what I'd want in the real world - I'd want complete independence for the transform/scale/rotation of the trees, different transforms/rotates/scales for the grass, different for the weeds etc.....

So, either I'm not adopting best practice or I'm missing something.   (BTW, I have watched the beginner tuts !)

Logic would tell me I need to create a new Forest object for each one, i.e. one for the grass, one for the trees and one for the weeds.

But if I do that, what about 'collisions' ?  (i.e. trees and weeds/flowers occupying the same 3d space on that same plane) ?

Can you give me some guidance please ?

Many thanks.

#### Michal Karmazín

• iToo Software
• Hero Member
• Posts: 1914
##### Re: Newbie question re collisions
« Reply #1 on: June 19, 2015, 03:32:44 PM »
Hi,

As you've mentioned:
Quote
Logic would tell me I need to create a new Forest object for each one, i.e. one for the grass, one for the trees and one for the weeds.
In most cases, that would be a recommendable work-flow for these purposes, at it's be better to create multiple Forest objects (for each type of vegetation), because this way you can have better control over those individually (like Transform).
Quote
But if I do that, what about 'collisions' ?  (i.e. trees and weeds/flowers occupying the same 3d space on that same plane) ?
If needed, you can exclude scattered items using another Forest object as described in detail in our on-line reference guide.

Hope that helps.

Best regards,