Creating a heatmap visualiztion in a pointcloud

I am having a very tough visualizing and therefore, implementing a heatmap within a sparse point cloud.i have to basically create a gaze-heatmap (on the inner walls of the room) out of the look directions of a player who has been playing within a room.
I have created the room as a pointcloud (implemented with a instanced mesh that uses box geometries). and then I have found out the intersection points of the player’s forward direction and the instanced mesh by performing a raycast. the room could be of any shape, or have amny different objects inside.

Any ideas as to how i can implement a heatmap visualization? will paramteric geometry be of any help?