Hi Jak Carver, where can we read about the solution in 4.18?
Will it do a realistic and working source-length to SPOT lights, so a spot light can be used for things like neon tube (lightning tube)?
They reoriented the source radius so that when you make a long tube light, it is oriented correctly, meaning instead of the tube length going in the same direction of the spot light, it now stretches out perpendicular to the direction of the light, making it possible to use spot lights for fluorescent light tubes for example. Just create a new spotlight in 4.18 and extend the source length and radius, you’ll see what I mean.
If you’re trying to make neon light tubes that bend and create custom shapes, this is still not possible. You would have to use an emissive material on a mesh and flag the mesh as an emissive object.
I have to disappoint you, it is not working. I installed 4.18 now and tested.
Yes, they have fixed that orientation and it stretches out perpendicular, that’s right. But it is only a editor fake. Only cosmetic. You see it in Editor, but the real light is not taking effect of it.
Here you see my test, i did a very long source length to test 400 length, source radius 5.
Then I rebuild Lights.
But the result is, that the light is not changing.
Still shine light a spot light with a small dot as source. See here:
And same on the ground, still a rounded spot light. Source length makes no influence:
That’s correct, that’s the way it’s supposed to work. The source radius affects several things, including the reflection of the light on reflective surfaces, and the shape of the light source for static/baked lights. Check the documentation for more details.