Are seam directions fixed? Can I draw a horizontal seam? A vertical one? By default, seams are perpendicular to the Default Counter Depth edge of a countertop, whether it is drawn left to right, right to left, top to bottom, or bottom to top. The Default Counter Depth can be changed under Settings > Quote & Order > Measurements.
If the Default Counter Depth is set to 25.5 inches, drawing in any direction results in a counter that is the distance drawn, and it's 25.5 inches in depth.
Seams are parallel to the Default Counter Depth edge regardless of the direction the top is drawn.
Seam direction stays attached to that Default Counter Depth edge, even if the dimension is manually changed.
To change the orientation of the seam, vertical or horizontal, keep in mind which edge began as a Default Counter Depth. Draw a counter, then switch the edge dimensions, and the seam will still run parallel to the original edges that were the default dimension.