Cull path modifier?

[Macker]

I am finding that one of the (inevitable) shortfalls of Growfx, or any tree creation software that requires the user to create the tree is that unlike real trees you end up with just as many branches in the centre of the crown as you do on the edges...

 

Real trees seek light, and do so by spreading outwards not inwards, and will "cull" branches and leaves towards the middle of the crown, also sometimes when space is an issue. I have tried to use the Path reaction modifier to get branches to reflect and avoid one another, and even an object reaction modifier (placing a sphere in the centre of the crown), but the former was useless and the latter was unrealistic looking, with branches suddenly changing direction for no apparent reason.

 

Is there a way to achieve this as the software stands?

 

If not, would it be possible to perhaps create something that places branches in a more realistic manner - perhaps something that generates a basic "hull" around the crown of the tree and culls, shortens or thins out branches towards the centre, using a falloff curve? You could for example have a "hull distance affects length/count/density".

 

I realise that generative/iterative software (arbaro, L systems, ivy generator) is far better suited to this as it calculates the tree and light it receives as it grows with each iteration, but obviously unlike growfx you lose complete control over how the tree looks, save a few basic parameters at the beginning.

 

Thanks in advance, and sorry if it doesn't make as much sense as it does in my head.

 

Chris

[Eduard]

Hi Chris,

 

Yes, to solve this problem, we want to develop a modifier (such as Trim or Eraser), which will trim the branches if they collide with other branches.

I think it will remove branches located in the middle of the crown...

 

Thanks!

[ptrain03]

Usually I find that if I just use the erase modifier to get rid of intersecting paths in the initial branches, (first three paths or so) the more inticate branchwork will have far fewer intersections. As far as the later branches, I usually try to arrange my branches in a way that allows them to take up as much spatial volume as they can without any of the branches touching. This isn't always how branches form, but I find that it is a good starting point.

 

The image below is a good example of how I try to arrange my later branches. I find that the newer a branch is, the more its form is dictated by its own internal instructions, which vary with each tree type.

 

Older branches (Initial paths) have had to adapt to the external environment for a longer period of time in order to survive and grow strong.  You can use the modifiers to sculpt these branches ( take out intersections, avoid objects, bend to accommodate prevailing winds, etc.)

 

 

Also the "Turn Axis" is a very important value to keep an eye on. It really helps to adjust this at different points along the path to prevent intersections. Many Times I set the value at the beginning of the path to around 180 (with initial axis angle at 90). This allows branches to grow horizontally towards the base of a branch where there is less space. As the branch goes out from parent, there is more space for it to grow, so the turn axis can be set to 90 or 137.

 

Right now there isn't really a way to do what you are proposing, however, there are existing tools that can get you where you need to go without too much extra effort until intersection detecting is implemented.

 

 

Hope it helps

 

 

 

[doncht]

Hi Macker, I'd be interested to see if you have a preview on this. Is there one already?