In AE CS6 I have 2 3D text layers swapping poition as the camera pulls back from them. One layer has a blur added and if I switch off the fx then they stay in the correct order.
The whole comp consists of 25 tiles (2500x2500px) laid out in 3D as a surface, it is a large map, and the text, which are place names, are at 90 degrees to it. I have placed nulls on the surface to to anchor lights and text to the correct points on the map.
I wanted a drop shadow behind the text to aid legibility against the background but since using a layer style breaks the render order in 3D space I have duplicated the text, made the front layer white and the back layer black and added a fast blur to the back layer.
There are expresions to fix the position of the text layers to a null, another expression that rotates both layers linked to rotation of the null that the camera orbits around and also a scale expression that links the scale of the text to the distance from the camera, so the text stays the same size in the frame no matter how far or close the camera moves. In the comp the text layers are next to each other, the white is the index number above the black.
This has all worked fine. The camera, pulls back, rotates around and the text faces the camera and stays a constant size in the frame. Then I was asked to tweak the move. Suddenly the two text layers swapped round, the black shadow layer obscuring the white text when the camera is in close. As the camera pulls back they go back to their proper positions. However if I turn off the fast blur then they both do what they ought too, white renders ontop of the black no matter what the distance.
Does anyone have a clue as to why?
Fast Blur is one of the hardware accelerated blurs. Check that stuff and set your comp to final Render quality to get an exact preview. Other than that this may simply be clipping issues, so adjust your positioning. Also I'm not sure why you are actualyl using an extra layer. Conventional effects are not affected by the same limitation as layer styles. Therefore applying a Drop Shadow would/ should work and avoid these issues.
It's not just a preview issue though, as it also renders out. So there's something going on.
My fall back was going to be to switch to 2D text and use an expression to link it's 2D comp position to the null in 3D world space.
Totally forgot about the Drop Shadow effect, I've been using layer styles for so long now, as there's more control control over the look, but Drop Shadow appears to be working.
Many thanks for that. A big help!