FreeCADHi everybody!
Playing around with the new Renderer Workbench, I had a feeling we could improve the new Renderer Workbench by adding some lighting functionalities. Here is my proposition:
Problematic:
At the moment, to set lighting in rendering, we rely on renders templates, with 2 flavors for each back-end renderer: standard, sunlight.
The main advantage with templates is that they require no tuning from the user. But there is a major drawback: it is not possible to adapt the lights parameters to the object you want to render, as all lights parameters are set once and for all in the template.
That being said, template is a good approach for sunlight lighting, because sunlight lighting is mostly independent from the object you want to render. And sunlight is naturally suitable for building rendering (arch).
However, there are other rendering situations for which sunlight lighting is not really suitable: part rendering, indoor scene rendering... For those situations, we need to light the scene with lights objects and we need to be able to adapt the lighting parameters to the rendered object. Those parameters encompass:
- number and types of lights
- positions of lights
- powers of lights
- colors of lights
- etc.
So we need mechanisms to do that in the workbench...
For all situations also (part, outdoor arch, indoor arch), we might also want to use image-based lighting (https://en.wikipedia.org/wiki/Image-based_lighting), which can offer some interesting lighting possibilities as well, especially with HDRI images.
Proposition:
My idea would be to add the following capabilities in Render WB:
1. An image-based lighting functionality.
It would allow to add an HDR image to the model, to be exported to the renderer.
2. A few lights objects, accessible via the WB toolbar, that could be added in the render view
In order to preserve the multi-renderer orientation of the workbench, it would consists in a small common subset of lights objects that could be handled by all back-ends renderers, ie:
- Points lights
- Areas lights (as rectangles)
Those objects would be exported to the renderers in the same way as geometry.
Those objects would bear an 'active' property (inactivated lights wouldn't be exported).
Those objects could be grouped in Lights groups, with an 'active' property also.
3. A three-points lighting functionality
As the above #2 functionality may introduce some complexity to non-advanced users, I propose to add a one-click action which would add a standard configuration of lights achieving a classic lighting scheme, the "three-points lighting": see http://www.3drender.com/light/3point.html, https://en.wikipedia.org/wiki/Three-point_lighting, or this blender plugin https://blender-addons.org/tri-lighting-addon.
For all those functionalities, I would replace the present "standard" template with a "dark" (or "flat") template, with no light.
Roadmap:
Collect the feedback from this thread and adapt my proposition.
Make a first implementation of the above ideas with Luxrender renderer.
Generalize to the other renderers once we agree on the result.
--> What would you think about that?
