Lighting behaving differently each side of origin

Development Rendering
, , ,
1

I have a large environment (built in 3dsMax) that I am importing into UE’s vehicle template. The environment is approx 1km x 2km and is approx 1.5km away from the world origin.
When I build the lighting all the pieces of model whose polys are located at X>0 are dark, but all those whose polys are X<0 are properly lit.
I have tried reimporting pieces of model, creating a new light, and a new lightmass importance volume, but all to no avail. If I change the directional light from Stationary to Static and rebuild the lighting then the pieces of model that were dark are now lit properly and those that were lit properly are now dark.
The ‘obvious’ solution is to move my entire model so that no parts of it lie in Positive X, but I feel sure I must be missing something. Can anyone shed any light on this issue please?

2

Hi BillB -

It sounds like with the size of the model you are bring in it could be overlapping and/or too small lightmap island sizes. If possible can you upload some screenshots of the issue and if you want we can look at the asset directly if you link a copy of the FBX.

Thank You

Ketchum

3

Thanks for your reply . Sadly I can’t upload any images because of a very strict NDA.
Do you mean overlapping polys? or overlapping lightmap uv islands?
Cheers,

4

I was referring to overlapping UV islands, my guess though would be that if you have a single unwrap for your entire environment at those dimensions you are getting light bleed because the unwrap is so compressed. At those scales I would recommend using only Dynamic Lighting pathways (Movable Lights) or break your environment up into much, much smaller sections.

Ketchum

5

Thanks again , the environment is in 66 pieces, none of which is much more than 100m across, and each has its own UVs, so I’ll look into dynamic lighting next…
Cheers,