Considering ies lighting

[tricky]

I am considering using ies lights with Erco data in a few of my interior renderings having never really used ies lights before. In general, will there be a big performance hit in using ies lighting over standard max spotlights?

[pengo]

in quality yes u surely have better quality, in rendertimes not good response i'd say

[Clifton Santiago]

Don't do it!

Actually, it depends on what you want them for. If you are trying to get accurate or realistic lighting levels, you can forget about it. If you end up changing the multiplier of the lights, or adjusting the exposure of the image in post, then you have completely negated the supposed accuracy you get by using them.

If you are using them for the light distribution patterns and ringing you get, especially on a wall washer, then they might be useful. However I often just fake it using radial gradient ramp map with lots of lines in it and put it in the light projection slot, to reproduce the hotspots and ringing you get in an IES light. It might be difficult to make the gobo resemble a specific IES however.

[tricky]

Initial tests show an improved quality of the rendering which (at the moment) justifies the extra rendering time. I will persevere for now and see how I get on.

[MikeHampton]

Yes.. I've found that I just can't quite match the light distribution and wall wash patterns of an IES light with any other type of light.

However you do take a hit in the render time. I don't have any hard/fast data on how much longer a rendering might take, of course it's going to depend on how many lights you are using. If it's only a few.. you might hardly notice a difference. If you have several dozen.. there could be significant difference.

Personally I wouldn't worry about it for a still, but might avoid them for an animation.

[siliconbauhaus]

Clifton,

I'd like to see some more details about your IES fake mate.

[victor.nsy]

vrayers,

just curious if you guys turn on use area shadow for IES light.
As far as my observation it's the shadow that's causing the
render time boom. If I am careful in apply shadow where I need
them ... my render time is still very much manageable. And
I don't use area shadow unless I badly needed one.

best regards,

[Clifton Santiago]

@siliconbauhaus: I just looked back at when I last used the fake IES, and instead of a procedural gradient ramp, I made a photoshop radial graident, because the procedural one takes too long to make look good.

In photoshop just start with a square image, then apply a radial noise-type gradient. Just keep hitting the randomize button until you get a pattern that looks good. Apply the gradient pattern and desaturate. Tweak the levels so its pretty high contrast. Add some noise or distortion if you think it looks too perfect, especially if you have a row of wall washers and you are creating several gobo maps so the light cone differs slightly from light to light.

Then drop it in the projector slot in a max spotlight. Test render and adjust the output until it looks good. It may not match a specific IES, but it will have ringing and hotspots like an IES.

One thing I am considering doing, is actually creating an IES light, projecting onto a perpendicular plane and texture bake the plane. That should allow you to create a gobo map that matches an IES.

[tricky]

Hey Clifton - you are 11 posts behind me!

[Clifton Santiago]

Yeah, I realized recently that my post count is getting up there. I'm in the top 30 now if you sort the member list by post count.

[tricky]

Wow - didn't realise that! Mind you, have you seen how many posts the first few people have placed??????????????? Do they have lives??????????