Author Topic: Lake - force displacement render method  (Read 342 times)

Offline mstasiuk

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Lake - force displacement render method
« on: October 03, 2017, 05:43:08 PM »
Next displacement question re. Lake, where the docs have nada:
Lake - top part of dialogue, render method pull-down menu: choices are default, force displacement and force ray trace. What is force displacement as a render method?

Online Dune

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Re: Lake - force displacement render method
« Reply #1 on: October 04, 2017, 06:57:58 AM »
Experiment a bit and you'll find out. You can use the rock object for some experimentation as well. With forced displacement the vertices are really displaced (so you need enough of them or the seams break), and with RT it's more like bump-mapping. 
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Offline Oshyan

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Re: Lake - force displacement render method
« Reply #2 on: October 05, 2017, 04:46:15 AM »
As with the other doc question thread, this is a newer feature that was added to all Object nodes and behaves the same in all object nodes:
By default objects are Ray Traced in Terragen. Unfortunately the current Ray Tracing engine is not capable of rendering true displacement on objects, instead it renders a bump map, which is effective at distance or with smaller "displacements", but does not show edge detail or larger changes in object shape caused by more significant displacements. The old "micropoly" renderer IS, however, capable of displacing objects correctly, but it renders objects more slowly and with lower quality. This is why Ray Trace Objects is enabled by default.

The Force Displacement option tells the renderer to use the Micropoly rendering method for that one specific object, so you don't have to lose the benefit of Ray Traced Objects on all objects (by disabling it in the Render node) just to get displacement on one. That being said, Force Displacement should not be necessary for the Lake object.

We are working on doc updates and will include this.

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Offline mstasiuk

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Re: Lake - force displacement render method
« Reply #3 on: October 06, 2017, 12:02:39 AM »
hi Oshyan,
thanks. So, I'm using a vector displacement to create waves on my lake object. Should I be using forced displacement then? Sounds like it. Otherwise my displacement maps get used as bump maps, which is definitely not what I'd like.
Mark

Offline Oshyan

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Re: Lake - force displacement render method
« Reply #4 on: October 06, 2017, 08:56:36 PM »
No, in this case it's not necessary. I neglected to mention that there are a very few native and *displaceable* objects. The Lake is one of them. The rest are on the Add Object -> Displaceable Object menu on the Objects layout, and they include Cube, Disc, Octahedron. Plane, Planet (yes, the planet is also an object), and Sphere. But displacement only works with these "native" objects. In that sense the "Force Displacement" should probably be removed from these objects.

- Oshyan

Offline mstasiuk

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Re: Lake - force displacement render method
« Reply #5 on: October 07, 2017, 12:15:21 AM »
thanks, great to know!