Cannot create small lights or 'spot' lights in cycles (trying to create a lampshade)

Hello BA,

I’m having some trouble creating ‘point’ or ‘spot’ or ‘lamp’ lights using cycles (in Blender 2.68a). What I’m trying to do is create a realistic ‘lampshade’ (as a minimum) with projected shadows. I’ve made several ‘meshagon’ lampshades and other math-based objects, see HEREfor more info.

I’ve tried many things. What you see below is my best result so far (sorry for the partial render it took all night as it is), where I’ve created a lamp object and lit it from within using a small cylinder with emission (strength = 10) property. Also shown is the basic scene, and a closeup of the ‘meshagon’ lampshade. The render properties are as follows:

  • samples = 10000 (probably overkill, i got the same result with 2000)
  • Light paths: Limited Global Illumination but with diffusion set to ‘2’ (bounces = 8, etc.) (note, i’ve also tried Direct)
  • clamp = 0

Note that in the World properties there is a property (default=0) that I set to “{‘sample_as_light’: 1}”. All the other objects have basic mix (diffusion + glossy, factor 0.2) properties.

So here’s the ‘problem’. I can’t get any reflections/shadows on the walls (see render below). If I turn up the emission of the ‘lamp’ any higher (e.g. strength=100) I get some nice shadows but there are tons of noise/fireflies and artifact even when clamping. I’ve tried varying all kinds of rendering properties and even sampled up to 10000 and still too much noise. The smaller I make the cylinder lamp inside the shade, the worse it gets. I’ve tried increasing and reducing ‘bounces’ (up to 32) and still same problem or worse. I’ve googled and studied various tutorials but nothing improves. Also there are few info on creating any kind of ‘point’ or spot light sources using cycles.

TL;DR: Trying to make a complex ‘lampshade’ effect in cycles but can’t make a small lamp or light source without excessive noise. Any help is appreciated.

Images: (note, for some reason I could not upload any images here… so here is an Imgur gallery.).
Also shown is a picture of what I’m trying to achieve.
Imgur gallery

ANY help or advice is greatly appreciated! thx.

Is your Light a Mesh-Light? I think the problem is the Light is too big. You get much sharper Shadows with smaller Lights. Try Point Lamp.
Then try to decrease the Sky or Room Light and increase the Film exposure.

Nice image of reference… but a fake any way. :smiley:

Simple experience: Bring your hand close to a light bulb and try to count your fingers thanks to their shadows on a wall a couple meters away. You might succeed… but if you see sharp shadows, consult an oculist. :wink:

I made a quickie.


Mesh light, strength set to 200. 800 samples with clamp at 10. There is still some grain but no fireflies… And it looks quite realistic to me.

That said, I tried with a point light too.


Point light with a size of 0.01, strength at 30. 400 samples with clamp at 10. (The mesh light is only for the camera. It has no influence on the scene.)

It looks immediately fake (and creepy IMHO). :wink: You need a mini-sun or a nuclear explosion to get such shadows but the lamp shade is definitively not enough lit. :smiley: Still, you can get closer from the reference image… up to a certain point. You"ll still get fuzzy shadows.

Thanks! That’s exactly what I’m looking for…

But I tried it in my scene and it’s still all grainy etc. Do you think you could email me the ‘quick’ blender file that you made here? Or could you upload it to rapidshare or something? There must be something in my scene that is set wrong. Possibly i accidentally goofed some kind of setting.

[email protected]

thanks.

Errr… Posting one’s email address in a forum isn’t a good idea. This is a magnet for spammers. :wink:

We can attach blend files to a post in BA. You just need to ask. Here is the quickie:

Forum Meshagon.blend (1.1 MB)

Enjoy! :smiley:

Thanks a ton!
Yes I know it’s kind of a ‘no-no’ to post my email but i’m not too worried. I get lots of ‘spam’ and have good filters.

Here’s my latest render based upon your advice. It’s starting to look good. thanks again.


Not really, though I get the point of your exaggeration. Light intensity, size of point source, and distance from shadow-casting object to shadow-receiving object all contribute to the sharpness of cast shadows. Keep in mind all those great B&W noir films with very distinct shadows cast across the scene, using real lamps! Contrived for scene design’s sake, you betcha, but not really fake.

@tcdoe: Glad I could help. And I must say that it’s getting really nice. :wink:

@Chipmasque: Yeah, I was exaggerating a bit. :smiley: The shadows looked too sharp to be real.