Announcement

Collapse
No announcement yet.

Leaves rotating and disappearing on UE4 with Oculus Rift when I move my head?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Leaves rotating and disappearing on UE4 with Oculus Rift when I move my head?

    I'm currently evaluating SpeedTree by importing the free "Broadleaf_Desktop" tree into UE4, dragging into my scene, and trying it out via the Oculus Rift. I haven't yet subscribed to SpeedTree until I can be sure that it does what I want, so apologies if my issues would be easily solved by editing the tree there.

    The main problem is when I stand under the tree and look up, and rotate the view (even without the Rift and with the mouse) then I see various billboard leaves rotating unconvincingly. Having this as the default makes no sense to me unless it is the assumption that in most games people will not stand under a tree and look directly up (which is almost exactly what they _will_ do in VR), so I'm sure I must be doing something wrong.

    I think I probably need to have trees with no billboard leaves and instead using geometry leaves. In which case the obvious question I have is: can I easily add geometry leaves in SpeedTree, and do the SpeedTree Store trees come with full geometry leaves? I'm hoping to be able to use SpeedTree to create my trees with almost no involvement of a 3D modelling package.

    To try to fix this within UE4 I fiddled with the "Facing Leaves" material and set the Geometry from "Facing Leaf" to "Leaf", hoping to prevent the strange rotation effect and fix the billboard in place. Which seemed to work, until I discovered that when I look at a tree from a certain distance with the Rift and move my head from side to side, then groups of leaves at the periphery of the screen seem to sprout from nowhere, and then shrink back into nothing again when I look back. Which would be a great way to freak people out, but not what I want in this particular game.

    My fundamental question is therefore: How do I get SpeedTree leaves to display consistently in UE4 when viewed from all angles in VR?
    Thanks.

  • #2
    Hello,

    The artist can decide to use camera-facing leaves or not. The same SpeedTree tools can be used to make a million triangle tree with individual mesh leaves, a super-low-quality tree with only a dozen giant leaf cards, or anywhere in between. Camera-facing geometry is still a valid technique for real-time trees because you can get a very full looking tree with fewer polygons. But as you saw, it affects the aesthetics since the technique breaks down when you get right up in the tree. We don't use camera-facing geometry a whole lot anymore, but when we do for a real-time tree, we usually fill the interior of the tree with them but use leaf meshes on the outer parts. This makes a good balance of speed and aesthetics.


    To try to fix this within UE4 I fiddled with the "Facing Leaves" material and set the Geometry from "Facing Leaf" to "Leaf"
    That will not work. The VB is packed differently for different geometry types. You could remove the SpeedTree node entirely from the material, but then all the camera-facing geometry will just point up.

    Comment


    • #3
      Thanks for the detailed reply. I guess that I need to sub to SpeedTree to edit the models for use in VR (ie. remove billboards) then - even SpeedTree Store purchases? Happy to try that out, especially because of your great subscription plan.

      Comment

      Working...
      X