Hi Eric, thanks for the explanation! I have only looked at the screenshots and there you did not show the construction script, so I thought you would have one Instance per Component.
So you are actually scaling all instances at once with just scaling the Instanced Static Mesh Component. Which unfortunately will not work for me, because I can’t just scale all trees, since every tree it growing for itself, and not all at once.
That’s why suggested to “scale” the mesh with a change in the material instead of scaling the instances because it seems to be not too efficient to scale multiple instances per frame, especially in a Hierarchical Instanced Static Mesh Component which I need because I need LODs.
Hi -
I am scaling every instance of the mesh completely separate of every other instance of the mesh, for my purposes I am allowing the engine to scale each instance randomly between a min and max values then in the Construction Script I am saving each mesh’s scale as an indexed component of an array that matches the indexed array of instances.
In the event graph on event begin play, I immediately set all the instances relative Scales to 0 and when the button is pressed in the project I lerp the 0 Scale to the stored original scale via a for each loop through the instance and instance scale arrays.
As I said for your functions, you would need to watch the array setup but functional it would work the same.
I worked up the WPO material setup but it poses a problem as it is driven by a Scalar Parameter which just like the scaling done in the example above would have to be driven by a series of arrays to make sure that you are using the correct variable or you will end up making all of them grow at the same time.
Thank You
Test Project
Hi Eric,
thanks a lot for your explanations and the project! It really looks great, but there are two problems, the first one is that it does only work if the tree is at exactly 0/0/0 and the second one is that it’s only scaling the tree in Z, while real trees mostly get scaled equally in X/Y/Z. Storing different growth values in an array would not be a problem for me, I’m already doing this with my HISMCs, but scaling HISMCs is just way too buggy, they flicker a lot. So if material scaling would work it would be awesome 
Thanks!
Hi John -
My project was a very simple implementation to show the concept only. You are correct you would need to find the center of the mesh based on an Object Position in the editor to allow for dynamic centering on the mesh. Assuming you can go in and edit the Pivot position of your tree, you could actually have it scale in all directions as well. And if I were going to use this implementation in an actual project, I would probably separate the scaling of the leaves as their own thing so you can have the trunk and branches grow then the leaves come in.
Thank You -