Rendering light confusions

I leave raytracing sessions leary of using lights ever again. maybe some responses to my confusions below will make the challenges seem more surmountable for me (and others).

1) Copying within a project: When Rhino 7 is behaving well, does using the copy command create an iteration of the original light so that if any copy (or the original) is edited, all the iterations change? When does it, and when doesn’t it? Tutorials have described this behaviour and I have experienced the confusion it can create, but I have also created copies which do not remain linked in that way. I don’t understand how to control and manage this. It seems there are some limitations with copied lights. Is it that they cease to respond to intensity adjustments, though further adjustments are registered on their settings?

2) Copying lights from one project to another: I copied (ctrl+c/v) a set of spotlights from one project to another but they seemed to have negible effect in the new project, despite drastic increases in intensity. New spotlights behaved more as expected. Is there a particular way to copy lights between projects or is it officially (or unofficially) unsupported?

3) Unintended light deletion: Is it just my setup, or does hitting delete to get rid of a number in a light’s intensity input field delete the light altogether from the project for everyone? This has been a shock.

4) “Shadow Intensity”: Help explains it, and I assume that Viewport display settings are applied in addition to each light’s shadow intensity settings. But how is this controlled when Rendering from the Render Panel?

5) A hollowing candle: How to create a facsimile of a burning candle where the wick has burned its way down a cavity into a glowing cylinder of wax? There is a) the glowing candle with a gradient of light scattering through the wax from a hotspot near the flame, b) light from this glow illuminating the immediate environment, and c) light unmediated by the wax going unimpeded directly up and out from the top of the candle.

6) Display colour of an emissive material vs its radiant light colour: How to match them? I find that to get a noticeable amount of (red) light from a material emitting red coloured light, I must turn the intensity of the emissive material’s light so high that the material glows completely white. The red glow it sheds is then unnatural.

I know that Vray is a popular substitute, but so is Enscape - which uses Rhino’s lights.

  1. Copies are separate copies unless you use History
  2. Copying is fine.
  3. What?
  4. The Render settings are separate from viewports
  5. That’s about using a realistic wax shader and setting it up properly
  6. To get realistic looking results without ‘hacks’ then everything about your scene lighting and exposure settings needs to be set up the same as you would for real photography. Your scene is probably too bright to actually see the glow you want.The shaders for the surfaces the glow is appearing on need to be set up realistically also.

Of course in “real photography” you take separate photos with the perfect exposure and lighting for each object you care about and hack it all in Photoshop in a totally unreal manner.

Have you got a decent Gamma correction factor for all your renderings? Lots of ‘why doesn’t this change do what I think it should’ questions are due to having Gamma stuck at 1.

Thankyou Jim


  1. Wish I knew why copied lights frequently seem unresponsive here.
  2. Hasn’t worked for me. WIsh I new why. The pasted-from-another-project lights can have the identical settings as lights created in a project, but cast almost no light at all.
  3. Using the delete key when editing intensity values for a light has deleted the entire light in several sessions. Not all. Today it’s not happening. Yesterday it was, and it has in many previous sessions.
  4. Got that from Help also thanks, but I haven’t found this adjustment for rendering from the Render panel. Help says that adjusting their Shadow Intensity controls the “size” of pointlights and spotlights. I don’t understand what that means. As far as I can tell neither has a “size” value with any meaning. (Their range is controlled by falloff, their intensity has its own setting, and their emanation point is a dimensionless point.) The size of a rectangular light doesn’t change at all when I adjust this value.)
  5. A physically based material, perhaps…
  6. With only one emissive material in a scene, there was no intensity setting resulting in a coloured glowing material casting that colour on nearby objects. I had to lower the intensity of the emissive material until the colour showed on it. At that point it eminated almost no light, so I had to add a separate light object do that. But - as you say - Gamma was at 1, so I’ll have to try it with a gamma adjustment.

Whether this light is on or off, Raytraced Display Mode shows it on and adjusts the ambient light instead. (Rendering from the Render panel shows the ambient light only when the light is off.):