View Full Version : Instanced geometry rendering problem

06-12-2014, 01:46 PM
Hey folks,

I spent a few hours yesterday trying to fine tune Global Illumination settings as I was getting some flickering issues. As it turns out though, the problem wasn't with the GI settings at all but rather with instanced items.

I reworked a model of the Lost in Space B9 robot and figured that would be a perfect application of the new Spline Control feature in 11.x. After encountering issues with splines imported from Modeler, I finally got the animation working and turned to fixing the GI flickering problem that I thought I was having.


At this point, the robot has come to a stop so the treads aren't moving. What's happening though is that some of the instanced treads are rendering partially "ghosted". There doesn't seem to be any pattern of which treads or which frames this happens.

I'm using an Image World HDR file but tested turning that off and using an area light instead, but no help. I haven't yet tried turning off Motion Blur but will later today. Beyond that, I've no idea what else to look at that might be causing this.

Any ideas or have I come across another bug?


06-13-2014, 04:31 AM
Motion blur probably. Hard to tell.

06-13-2014, 04:50 AM
Which instancer are you using?

06-13-2014, 09:38 AM
Did some tests yesterday. Turned off MB and that indeed got rid of the problem. Didn't know there was anything other than Instancing in LW 11.x other than what's built in unless Denis's DPKit has something.

Odd thing though is I stripped the geometry down to just the splines, the tread objects to instance, and the base that they rotate around and couldn't get the problem to occur. So, I need to do more dissecting to see what's going on but haven't a clue as to what might be interacting like this to make some of the treads sporadically "ghost" render. Guess I know what I'll be doing this weekend.

The Offset of the Spline instances are enveloped using the Follower modifier that's controlled by a null. The problem is happening after the last keyframe though and looking at the graphs confirms that there's no movement.

06-13-2014, 10:04 AM
I feel your pain...