Challenge with lighting technicalities

I’m having great difficulty lighting my models and this is most likely due to my lack of expertise rather than any shortcoming in Rhino - but maybe someone can help?
After many hours of experimentation with all light types I have eight lights in the model - 3 spots and 5 rectangular lights.
I avoid point lights because they create a harsh reflection on the water and linear lights create out of place linear shadows.

The biggest problem I have is I’m getting too much light in the cockpit in the centre of the boat and not enough light on the outboard hull sides.
The area just to the left of the mast in the image below is a good example of this.


I’ve turned most of the lights off and created a rectagular light and placed it beside the hull where it won’t shed light into the cockpit - but all the light is concentrated at the forward end of the rectangle. maybe I’m not using this light correctly?

src=“” width=“690” height=“316”>

I expect I could deal with this problem by adjusting the material reflectivity attributes but as I have posted elsewhere applying or modifying materials in models over about 10MB locks the CPU up for very long times often requiring a restart.
This last image shows another problem area at the back of the hull on the far side. It has way too much light while the near side hull has not enough.
Skylight is turned off as it floods the scene as others have noted.
In fact the default lighting in Rhino (without any added lights) is quite good. The main drawback with it is I don’t have the same control over transparency of the textures.
Thanks kindly for any words of wisdom.


I agree with your use of less lights… this will speed render times. The screenshots above look like they’re all from the rendered display mode though so I’m not sure if you have actually ‘rendered’ the model yet. Forgive me if I’m confused but have you clicked the render icon (blue sphere) or run the Render command? This will ‘raytrace’ the scene which is a way of saying light and reflections will be calculated more realistically than what you see in the rendered display mode.

If you can post a model (doesn’t have to be this one), I’ll take a look as well to give you some pointers.

Thanks Brian, You’re right - these shots are all from the rendered display mode. I’ve discovered a major part of the problem. I had moved that rectangular light so close to the hull that the arrow from the light was touching the hull.
However the light in the cockpit remains, even with the model rendered.

I’ve checked there are no rogue lights in the model by turning off all elements except lights in the viewport settings.

I’m going to see if I can resolve this problem by adjusting the relative distance of the lights from the model and adjusting their intensity. I’ll post back if I can’t resolve it.

Hi Tony- I would say you have more lights than you need - I’d cycle through them one at a time and see which light is doing what - you may see that you can eliminate some. One trick is to temporarily assign matte white material to everything, and color the lights you are testing (if more than one) so that you can see clearly which light is responsible for what.


Thanks Pascal - yeah that sounds like a practical approach and I’ve already spent a lot of time doing exactly that. Here are some more images that illustrate the problem with just one light on.
Its a rectangle light about the same dimensions as the side of the hull. It’s placed below the deck line so no light should be able to shine on the far side hull.

The reason it’s at an angle and not parallel to the hull is because it directs the light off to the left -towards the bow. I had the same problem with the linear light.

This third image shows the light concentrated in the middle of the close hull rather than spread evenly as you expect from a rectangular light, and light flooding into the cockpit and onto the inboard side of the far hull at the stern.
This occurs again and again regardless how I play with light selection and placement - and I get the same effect in my other models as well.
The fourth image is the same settings in rendered mode.

src=“” width=“690” height=“368”>


One would think there must be another light in the model but there is not as I’ve checked with the viewport settings

To eliminate the possibility of it being a reflective problem I replaced the material with White Matte and removed the water surface.

Applying the material took 4 minutes.

Screenshots are viewport and render modes. I also turned skylight on but it floods the scene with light in both modes.

Update: I’ve added an environmental map and turned all lights off - so default Rhino lighting. This has provided an acceptable render although still with too much light on that inboard transom at far right. Could the background setting have something to do with this problem?


I would make that side light much smaller. (BTW, these do not cast shadows in the rendered display but do in the full rendering.) Maybe post your model to via to my attention, I’ll take a look…


Thanks for the extra information. Please send over a model if you haven’t already and I will try to help more.

The Rendered display mode of rectangular lights will show a highlight that is more similar to a spotlight. It’s only when you actually render with the rectangular light that you’ll see this light more evenly spread. The material of the object being lit is also a factor. If you can’t send the model, please just replace it with something else that shows the same lighting questions and send that to tech or post it here.