I think it's a great idea.
You'll need to have sides on it, of course, to stop the tortoises climbing out and likewise the ramps will need high sides to prevent the tortoise falling off.
But as a basic drawing to provide more space, it's very imaginative, a super beginning.
The problem with multiple levels for a Russian tortoise is that they really like burrowing, and this sort of setup doesn't really let them. It's certainly a creative way to add additional floor space though!
Super cool, but if it has tall sides, make sure there is still space in-between to reach in and get him out from the bottom shelf! I love the idea! Can you make me one?
Looking good.
But don't forget you'll need a good few inches of substrate in each level for burrowing and then enough height on the walls to prevent escape.
One potential problem is the steepness of the ramps in your CAD plans. You can help this be simply making the ramps longer by changing the attachment points.
Also remember that each level will be its own enclosure and you will have to heat and light all levels.
I really am at a delma I know i need a bigger habitat but my mom do not think so and i dont have the space for an 8 by 8 and i wish i could find something cheep and space saving i could keep my Russian tortoise in