Light coming behind a door

palexpereira

Hey guys,

I'm new to UE4 and I'm having big problems lightning this scene. I need to make a light shine through the door down the corridor so to make the blood stand out. Also I need the ceiling lights cast light and that doesn't seem to be possible with emissive maps. I used a skylight and some sphere reflection capture to even out the light. But nothing still looks convincing



On any other 3D application I would use an area light for this effect. Instead I had to use a spot light with an almost 90º angle, cause I really have no idea how to do this.



Any help and criticism would be welcome

Khaja

I'd check out the unreal lightroom(?) content on the marketplace. It's Arch Viz but has a nice setup with the lighting to create the area lights you're looking for (i think)

Vailias

Perhaps this will help? https://docs.unrealengine.com/latest/INT/Engine/Rendering/LightingAndShadows/Basics/index.html
"Larger radius lights cast softer shadows (like area lights in most major 3D authoring packages). Since this is being processed by Lightmass, only Static lights will gain the effect."

You will, of course, need to bake lighting for that.

If you need it more realtime, you may be able to fake an area light with a grid of point lights. I used to do that back in the day when I didn't want to wait hours for a raytracer to figure out an area light.

palexpereira

Vailias wrote: »

Perhaps this will help? https://docs.unrealengine.com/latest/INT/Engine/Rendering/LightingAndShadows/Basics/index.html
"Larger radius lights cast softer shadows (like area lights in most major 3D authoring packages). Since this is being processed by Lightmass, only Static lights will gain the effect."

You will, of course, need to bake lighting for that.

If you need it more realtime, you may be able to fake an area light with a grid of point lights. I used to do that back in the day when I didn't want to wait hours for a raytracer to figure out an area light.

Thanks a lot! Is it less expensive to do a bunch of point lights than one area light? I didn't know that

JedTheKrampus

A bunch of dynamic shadow-casting point lights are going to be WAY more expensive than baking a lightmap. You would likely be able to get the effect you want with distance field raytraced shadows as well, although that takes a bit of setting up.

Vailias

The cost totally depends on your renderer. Back in the day area light capable raytracers wound up casting a huge amount of rays for area lights of any significant size, while the quality compared to a bunch of pointlights was not terribly different so long as the relative angle between each point light and the object was fairly small.
Yes a bunch of dynamic shadow casting point lights will be way more expensive than baked lighting, even of those same point lights. I'm not sure how it compares in a deferred setting, but its still going to carry a cost.

Also if you need the ceiling tiles to emit light, you're going to need to put some lights there. There was a feature for a while where textured geometry could emit light, but it has since been removed since it didn't work to Epic's satisfaction.

JedTheKrampus

The cost doesn't come so much from the additional lights as it does from the additional shadow casting. If you didn't need the shadows for those lights the cost would be pretty reasonable.