# How to fake parallel lightbeams and shadows?

(labyrinthe) #1

Hello,

I’m trying to cast shadows from a sun. The lightbeams and the shadows should be parallel.

The only way I know to cast shadows is by a spotlight, but the rays are not parallel and so the shadows are wrong.

I succeed in having parallel lightbeams with a sun and the Halo button, but it didn’t cast any shadow.

Does anyone have some ideas?

(haunt_house) #2

do the have to be exactly parallel? if you move the spotlight VERY far away and adjust the clip and dist values…

Not even the sunrays are perfectly parallel.

HH

(pofo) #3

I was just about to suggest the same thing. (and sunrays are parallell unless you work with a model of something very, very big. but you don’t really have to put a spot that far away for the angle to be innoticeable)

1. pofo

(haunt_house) #4

Sunbeams appear to be parallel, just because they are very far away, but they are not.

they are just ‘parallel enough’

or do you mean a blender sun?

HH

(labyrinthe) #5

I will try the “Far away spot / parralel enough” way of blending…

Thank you for answering, and especially for the blend file! Very accurate answers.

(pofo) #6

Well, the angle between two sunbeams a metre apart would be about 4 x 10^-10 degrees (0.0000000004) so they’re not parallel in a mathematical sense, but in a physical sense they are since it doesn’t get much more parallel than that (ok starlight might be even better). Much more parallel than say the edges of a paper or whatever.
Not that it matters though

1. pofo

(bob_dog) #7

Parallel or not, just remember one of the golden rules of 3d work:
If it looks good, then it is good.

(pofo) #8

And if it looks evil then it is evil

(haunt_house) #9

And if it looks evil and big and hungry, run away!

by the way, the overall direction of sunbeams is almost parallel, but since the sun is not a pointshaped lightsource, but a ball of 1.4 million kilometers, they are actually quite unparallel.
HH