During modeling operations, BricsCAD respects your design intent.
When creating a flange, its initial position places a body above XY plane. It is like your design is laying on the table. The bottom face of the newly created flange is called a reference face. You can distinguish it with a slightly different color. The reference face maintains its position when you change its thickness.
You can control the position of the flange with the Control hotkey.
Your overall design intent of the initial flange size is maintained during the creation of other sheet metal features.
As you can see here; the overall dimension of L-shape model is still 50.
If the length of the vertical flange is 50 and we add a horizontal flange - overall vertical height of the model is 50
Let's switch to the second case. It is dimensioned polyline.
While extruding the polyline, you see that all dimensions are kept. This is important for proper design.