Hello, everyone. I am working my way through hard surface modeling, and have been going over Chris Kuhn’s book Blender 3D Incredible Machines. I have gotten to the part where the Edge Split modifier is introduced, and I am encountering some unexpected results when I enter different values for the edge angle.
The standard definition is that any angle between two faces sharing an edge that is equal to or greater than the entered value will be split (sharpened). However, the first screenshot shows an edge angle value of 40.4, which causes the edge to be split. The next screenshot shows an edge Ange value of 40.5, which causes the edge NOT to be split and leaves it smooth. The angle is marked as a value of 139.56318.
I guess I am not understanding how the angle that is marked with the MeasureIt tool relates to the value that is entered into the Edge Split modifier. I would like to really understand this before I move on.
If these faces are in the same plane, however, they should not be split because there would be 0 deviation from one surface to the next.
Below is an example, and are the same simple models, both have subdivision applied to show the edge spitting better, the highlighted models have edge split active at a setting of 30 degrees, while the one that is not active has subdivision only. You can see how the one that is deflected slightly has the edge between the adjoining faces split.
Hello, ajm. I am still a little unclear. The angle that I have there in orange (139.56318) is the angle between the two faces who share the edge, and is indicated by the black arrow. The edge sharpening takes place around a 40 setting in the Edge Angle field, yet the angle that is measured by the Blender tool MeasureIt is 139.56318, so I am a little confused by why the value entered in the field and the measured angle between the faces is different.
As in the example I provided, the angle of deflection of the faces is what is measured when using edge split, so if you were cut a piece of paper to the same shape it should not split the edges, only when you fold that piece of paper along that line would the split occur. The angle that you highlighted as measured by Blender is the angle edge to edge along the lower boundary of the shape.
I’m afraid I still haven’t gotten my head wrapped around this yet. I am sure it is pretty straightforward once it is understood, but I just am not there yet. In your second diagram, it shows a top view and a side view.
Just for clarity’s sake the diagram I originally gave was more of a 3/4 perspective view, not an orthographic top or side view, with the angle shown of the the two faces which are connected by the common edge. I am not quite sure what you mean by Angle of Deflection. Would that mean the angle that a part of a line deviates from an imaginary continuation of the original line
It’s measurement shows the inner angle. It will show 180 for two flat faces, and the edge split will see a zero degree outer angle. Just subtract the displayed angle from 180 to see the deflection angle that the edge split is looking at.
