To ensure that the fabrics are to scale when we drape them onto a product we need to know the dimensions of each fabric and the dimensions of the product to be draped. Both inches or cm are fine. In this case we have a fabric and a shirt, but it could be anything, a tile and floor, a table and wood...
This is what the fabric would look like if a ruler had been placed next to it. You would not have to send us an image of the fabric next to a ruler (Although if we were placing the fabric into repeat this could be an option). All you would have to send us is the image of the fabric and the fabrics dimensions, width and / or height. For example the fabric below has a width of 14cm. Or (only if we are placing the fabric into repeat) you could say the gap between the green dots is 3.5cm
Here the fabric has been place into an endless repeat. If you are sending us a fabric image that has already been placed into an endless repeat you will need to send the dimensions of the image. For example the fabric below has a width of 15cm
You would not have to send us an image of the product next to a ruler. All you would have to send us is an image of the product and the dimensions, width and / or height. For example you could just say that the width of the shirt at the base of the image is 25cm
We now know the dimensions of both the shirt and the fabric. So now when we drape the shirt it is to scale.