What causes?

Do you mean like when the object textures clash against each other?
That's called 'Z-Fighting' and it's caused by two pieces with different textures being exactly flush. You can fix it by picking up the piece, holding the left stick in to go slowly, and moving it slightly up/down-left/right.

Hope that helps.

 

I think he's referring to when some pieces light up completely, and kind of flash a few times, not Z-fighting. I'm not %100 on this, but I think it has something to do with there being too many pieces on-screen at one time.

 

That's pretty close.

In Halo 3 that only happened when you use the ultimate budget glitch, and was one of the reasons the budgets were so low.

Never happened in game though and in reach it's the same. It will happen when you are off a ways in forge and looking back at the whole of the created map but it will never happen in game.

However, if a map you make does this then some of the longer lines of sight will suffer from frame-rate lag.

So be mindfull of it.

 

I had this flickering happen on my current project when far out. It wasn't the cause of my lag, though. I went hunting for planar clipping (z fighting) and found that there were lots of minor parts clipping when the LOD (level of detail) is lowered by being far away. Now I can zoom far away and still get those flickers but no lag. And yea, I'm pretty sure it's from using so many parts, especially kill zones and spawn points while they are visible. They seem to cause it big time.

 

Definitely from having too many objects on the map within view... usually when viewing it at certain angles. Most of my Halo 3 maps were like that. That strobe light effect was pretty annoying. It would happen in games as well, if you have a map that allows you to view the entire map when playing the game... getting in flying vehicles or in Reach, using the jet pack to get an overhead view of the entire map.

 

This is pretty accurate, im not gonna lie, but LOD is such a crap acronym

Its called rendering; if the object is incompletely rendered then it will have a lower level of detail. The closer you get, the more completely it renders the object.

Original post, its caused by having too many objects on screen at once, causing the render to become confused and not understand the lighting. It effectively lowers the render beyond what bungie intended as the lowest level.

 

LOD is a very common acronym for it, actually. Rendering is the process in which an object is visually generated. For instance, your statement is almost correct. The further away you are from an object, the polygon face counts are lowered and the object is rendered at a lower quality also called the level of detail.

Edit: Today I noticed that the Round Bunkers have a planar clipping issue by default. Where the small black strip meets the thing grey stripe, it is very noticeable. Any ideas if Bungie was notified and whether or not they will be fixing it?