hi…
switched ON caustics in object properties for transprent obj.
switched ON caustics receiver in object properties for floor.
switched ON caustics in light properties.
switched ON caustics in cycles render properties.
switched ON transparent shadws in material properties for transprnt obj.
still im not seeing transparent & color shadows on the floor !
plz guide
thank you
Hmmm I can’t tell what your missing…
the only difference I have , as far as I can tell, is I used a spot light instead of area…
I used same version of Blender and have all the same settings…but I only have the light set to 3000w, and I also have an HDRI to brighten up the scene…
Maybe watch this and see if you missed something ( ignor the download of the special build as it is contained in 4.1)
One important thing (you did not mention) is that you need to set the glass object to smooth shade for it to work. (and maybe add a slight bevel to avoid weird reflections)
Caustics.blend (109.9 KB)
Here is the same scene with the glass set to flat shade.
Yes it was a very quick example, I should have paid more attention, if you apply the scale you need to set the bevel modifier better, I should have done the bevel something like this;
That way it is adding support loops to keep the surface flat with smooth shade on.
You could also use auto smooth by angle and get rid of the bevel.
The important bit is that the glass has to be smooth shaded for the caustic option to work.
Hello,
switched OFF caustics in object properties for transparent obj.
switched OFF caustics receiver in object properties for floor.
switched OFF caustics in light properties.
switched ON caustics in cycles render properties.
switched ON transparent shadows in material properties for transparent obj.
No smooth shade needed and real flat bevel …
(The base file is that of @DNorman)
hi bros, thanks for all your response. 
i switched OFF the shadow Caustics in light properties and i got the color shadow.
And found that if the mesh shape is complex like diamond , and further to it, when i applied more shader nodes (only those shadr nodes thats necessary for a mesh to look like diamond), for the light ray to penetrate, then color and twinkling shadows are not so prominent.
