A lamp act as a lamp, therefor the hot spots (if I understand correctly). There is also something like environment light. Light coming from all directions (light scattered sun). People use HDRI environmental maps for that.
The sun isn’t working because you’ve probably created a room as a box. Which is block by the box.
To get a diffused light, draw a flat plane. With the size of the, imaginary wall, behind the camera. And add an EMISSION shader , which generates soft light. Tweak the emission strength and color.
If you want to use the sun lamp, an easy setting to prevent the room/wall from blocking the sunrays is by deactivating the ‘shadow’ option in the object setting of the room object (under ‘ray visibility’ group). Hope this helps.
This reply was modified 7 months, 4 weeks ago by purbosky.
To see if the sun lamp works or not, you can delete or hide the spheres/mesh light so the only lighting comes from the sun lamp. Another alternative If you want effect like sunray from windows like in the attached image, I delete one side from the cube/room and rotate the sun lamp so that it light the room (the ‘shadow’ option on the room object need to be turned on though). If you want, the sun lamp can also rotated so that it’s perpendicular to the room opening and will light the entire room. I then use a second sun lamp with higher strength and rotate it so that the rays cast through the windows. Note that the sun lamp position doesn’t matter, only its rotation.