I am wondering if this can be done as DIY

http://www.largeluminoussurfaces.com/onespace

What material for the white panel that I can buy? It seems like some half-transparent solid white "plexiglass" / acrylic sheet? I don't like the one in HomeDepot where it has patterns and stuffs. I can build a box and put the lights inside.

I am seeing similar things in the mall where people make the clothing display platform

Can someone advise me on the material? Thanks