OTOY Forums

I was rendering a scene with planet earth and a spaceship hovering next to it, and I realised that using daylight in not appropriate for this type of scene where you want the earth to falloff into complete darkness and don't want a skylight or fill effect over the whole planet. So what I needed was a single directional light placed far away to gradually fall away into black over the earth, while also illuminating the ship.

I used the octane light, set it to sphere but it's maximum power is only 100,000. In my scene of such scale, it barely lit anything. Turning my exposure up helped a little, but also started to reveal odd artifacts in the image because I had to boost it so high. It just wasn't bright enough.

I scaled everything down which worked a lot better, but that's not an ideal solution, and I still couldn't get the look I wanted with the current lighting options. Please add an option within daylight to not use the ambient sky/fill and also add directional lights with cone and falloff if that's possible? Sometimes we need more than one powerful direction light in the scene.

The current octane lights are good but IMO are not flexible or powerful enough for many situations.

Yeah, the limits in octanerender - the sad thing. Especially IOR≤8

Their is a trick you can use. If you set your emitter to a proxy then when you scale your object your power remains constant. So to test with your sun set your to a small scale then maximum power go to 100 000, then set to proxy and scale and position your sun object far. Test this for yourself .

Thanks Matt, I'll try it out, but off the top of my head would that not give softer shadows? One of the reasons I set my sphere light to be very small is so that the shadows it produces are sun-like and sharp. The bigger the sphere, the softer the shadows. Or does the scaling produce a different effect on the shadows that setting the sphere size in the properties of the light?

Even though my scene is big, it isn't anywhere near true scale, so my sun is actually fairly close to the planets (so it needs to be small and powerful to produce the crisp shadows). Scaling it up means you'd have to move the light even further away to keep those shadows so you lose the illumination you've gained by scaling. It seems like a catch 22.

I'll try it out anyway incase the scale trick is doing something odd, or there is a magic compromise which works. I wish we just had directional spotlights

Hi darkline,

Try increasing the "efficiency or texture" as well as the power.
Also, for a scene like this you will never be able to have it in 1:1 scale in octane. The sizes you will be dealing with will start causing artifacts due to single precision floating point precision problems. So after increasing the power and efficiency and crispness of shadow, scale the scene down until it is lit to your liking.

Thanks
Chris.