Displacement disabling itself

[fyckfaco]

Heya, does anyone know why sometimes displacement seems to turn itself off in the interactive render.
I have rocks in a scene with displacement turned on within the material, I have to tweak the max min values to remind it to work with interactive.
As soon as I change camera view and unhide some stuff it turns off again.
I'm hoping its not something that occurs with the normal renderer, I have only noticed it with interactive so far.

[TomG]

"change camera view"

In order to save memory and render time, Screen mode is the default for displacement. It is calculated before rendering, based on what is seen in the view - if you then change views with IR running, displacement is not recalculated, and if that view is looking at something not seen in the previous view, the displacement will not have been calculated there. All by design :)

Options are to use World Space for displacement (with the associated cost of greater memory requirements and longer to calculate displacement on render start up), or to stop and start IR if you change camera view.

[maru]

Yep, what Tom said.
You can just right-click in IR and select "restart" to re-calculate displacement.