Floor tiles material - match size for multiple rooms in house

Question

I'm making a house from a floor plan.

Each room has its own plane to be unwrapped and assigned the same tiles material.

Whenever I unwrap a floor plane and assign its material, the material scale is different for each room and I have to eyeball the scale to make the tile seams align.

Is there a more efficient way of unwrapping all planes so the tile seams align properly, or do I just have to give in and make all floor planes into one object?

Cheers.

EDIT: Added picture

In the picture below you can see the floors were unwrapped but each floor scaled differently. On floor has small tiles and one has large tiles. I'd like to unwrap each floor so they have exactly the same scale.

Answer 1

For a floor material, there's no need to use UVs.

Use the position vector on the geometery node to get an even (world space) mapping for the floor. You can then just use box mapping and adjust the scale in the material. It will be applied at the same global scale regardless of individual object rotations or scale.

It will also be 'stuck' to global position so moving the floor will result in the texture sliding across the surface. If that isn't desired you can apply scale and use the object vector.