Thermal Shade Analysisi failed: Attempted to divide by zero

Hi everyone, would anyone let me know why I am getting the “Attempted to divide by zero” error?

I am using the downlaoded script from gitbub (comfort_shade_benefit) to analysis shade benefit. All step retaimed the same as the original script. But I used my own shade geometry and study region, I also added context buildings.

The script only worked when I adjusted the grid size to be 1 or above. Once its below 1, it will fail. I want to understand why.

As a new user I cant upload files. But please see the screenshot for the script:

Much cappreicate for your help.

I can only upload one image once. Here is the closeup of the error mssage

This is my context buildings and shade geo (green):

This is my study region (blue):