First you need to create a cornel box in maya like this.
Then export to guerilla render and adjust the resolution project size to 500 x 500 px.
Select the camera as a camera render.
Create the shader for the light and for the objects like that.
Enter this indirect diffuse parameter :
Create a new layer as a Point Base Gathering, and assign all of the point cloud with the indirect diffuse of each shader you have create.
Link all primitive you want, and link visible and matte.
Check color bleending in your point based layer and enter 4 bounces. Render it and it should be like this
Now we have to add some diffuse information to the point based layer.
Create an output in your Point based layer and rename it « Diffuse »
Then in your output shader create one more and rename it « diffuse » too. Conect the color output to that diffuse output.
Render it again and it will be like this.
An little comparison of the difference between before and after the diffuse information.
More render with another blue color, a pink torus and an 2d texture for the cube.