Kia Ora

Can I use a portalspace or subspace to set a different lighting eviroment is a lower area of a cell?

I have a home setup with a nice ambient lighting and it has a dungeon/celler area down stairs I'd
Like to darken, I know I could do it by making another cell, is this the only way?

I'd like it to be walk through and not have a load screen

You can create a room marker for what your trying to accomplish. Once you create it around the area of your liking, double click the marker and go to "bound data" in its properties and can set individual light settings, you can also create a custom light templates.

http://www.creationkit.com/Bethesda_Tutorial_Optimization

Setting the lighting template in the cell window will apply that change to the entire cell, but we can also change the template on a room by room basis.

That sounds like what you want to do, the above comes from the CK Wiki Specifically http://www.creationkit.com/Bethesda_Tutorial_Lights_and_FX.

Edit: ah I'm too slow

Kia Ora

Thank you both for your help,. this sounds easyer than activators and pull chain doors

Edit:

Learned the hard way not to leave anything outside the box a,.. I could figure why bits where missing till I spotted the
Bits outside the blue boundaries