Lighting design, especially accents - ideas and implementation

Dear fellow campaigners and those seeking help,

we are currently getting into the topic of electrical planning, lighting planning, etc. and are currently managing by transferring the floor plan into PowerPoint and now adding lots of "markers" and icons.

Is there freeware that can help us here or a PowerPoint icon set that is available? We couldn't find anything.
Regarding lighting planning, we are still looking for a small software for, e.g., a simulation. Does anyone know if there is freeware or possibly suitable planners from manufacturers that can be used?

Many greetings and thanks a lot.

DIALux for (professional) lighting design and precise simulation. The software is free of charge. It requires some time to learn, but once your house is modeled, you can display and calculate all kinds of lighting scenes visually. For electrical planning, I used RedCad. Very simple 2D planning software with a very short learning curve. Unfortunately, not free of charge.

As already mentioned, DIALux is the tool of choice for lighting design. However, I can't say much about the program since, at our company, I go to the "lighting" colleagues with questions, and they work with it.

Great! That is much more than I expected! Thank you.

Since we have a sloping plot and our house is built along the slope, the rear area of the house slopes down.
At the top, we do not follow the offset – this results in a higher ceiling height in the living/kitchen area on the ground floor at the back.

Coming from the front door, you can look all the way out again through the small staircase (1.40m) leading down.
Does anyone know how I can implement this in DiaLux? We want to illuminate the staircase and the open corridor leads past the coffee bar into the dining room -> We are planning different lighting scenes there.

Does anyone here know how I can implement this in DiaLux?

Where do you see a problem?

It's resolved. User error - was able to fix it with the cutting tool.