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Smooth asymmetrical anchor points in Expression Design RRS feed

  • Question

  • In Expression Design 4, after using the Convert Anchor Point tool to convert an anchor point to a smooth point, it constrains the handles to be the same length, i.e., the anchor point is smooth and symmetrical, How do I get the anchor point to remain smooth, without it being constrained to be symmetrical, i.e, allowing the lengths (but not the angles) of the handles to be adjusted independently?
    Saturday, December 17, 2011 4:25 PM

All replies

  • Hello Tim,

    Depends on how the line was created. With the Bezier (pen) tool, I believe one can only cusp and symmetrical nodes. Using the paintbrush tool, one's choices for a node are the cusp, sym., and smooth.

    Take care, Mike

    Sunday, December 18, 2011 2:09 AM
  • Hello Tim,

    Depends on how the line was created. With the Bezier (pen) tool, I believe one can only cusp and symmetrical nodes. Using the paintbrush tool, one's choices for a node are the cusp, sym., and smooth.

    Take care, Mike

    Actually that's incorrect. You can create smooth asymmetrical nodes with both the pen tool and the brush tool. The problem is that once you edit the node with the Convert Anchor Point tool, there is no way to convert the node back to a smooth asymmetrical node.
    Monday, December 19, 2011 12:53 AM
  • Tim, Just click the point again with the Convert tool and drag out the handles; you can also hold the Shift to constrain the angle.  Does that help?

     


    ~Fred

    • Edited by Fred C_ Monday, December 19, 2011 1:19 AM
    Monday, December 19, 2011 1:18 AM
  • Tim, Just click the point again with the Convert tool and drag out the handles; you can also hold the Shift to constrain the angle.  Does that help?

     


    ~Fred

    Hi Fred,

    Dragging with the Convert Anchor Point tool will create a smooth symmetrical node, which is the point I was making in my previous posts.

    There are two types of smooth nodes, smooth symmetrical and smooth asymmetrical. By smooth asymmetrical, I mean that the two handles are pointing in exactly the opposite direction, but it is possible to adjust the lengths of the handles independently, as in the second illustration shown below, taken from the documentation at the  following link.

    (http://msdn.microsoft.com/en-us/library/cc294502%28v=expression.40%29.aspx)


    • Smooth point   Each control handle of a smooth anchor point is extended and the two handles are pointing in exactly the opposite direction (180 degrees) from each other. When you first draw a curve with the Pen tool, its handles are symmetrical. In other words, they're positioned the same distance away from the anchor point.

      Symmetrical handles on a Smooth point
      Cc294502.096ae76b-9a82-4582-b144-4db3060bb6ea(en-us,Expression.40).png
      After dragging one handle with the Direct Selection tool, the handles are no longer symmetrical, but the point is still smooth
      Cc294502.20ba0a8b-7e24-4d09-97e2-bd4cb6d77ab3(en-us,Expression.40).png

     

    As the document correctly indicates, when the curve is first drawn with the Pen tool, it is possible to modify the node with the direct selection tool so that the handles are different lengths. The problem is that once you edit the point using the Convert Anchor Point tools, it is no longer possible to adjust the lengths of the handles of a smooth node independently.

    I found another post for the same issue, but no one responding seemed to really understand the question. (http://social.expression.microsoft.com/Forums/en/design/thread/4a5f0b35-e42d-482d-8df3-f8b7cb52fc7f). I hope my explanation helps clarify what the issue is.

    Thanks,

    Tim

    Monday, December 19, 2011 2:43 AM
  • ...The problem is that once you edit the point using the Convert Anchor Point tools, it is no longer possible to adjust the lengths of the handles of a smooth node independently.

    You can use Alt and drag a handle independently and Shift to constrain it.
    ~Fred
    Monday, December 19, 2011 1:54 PM
  • ...The problem is that once you edit the point using the Convert Anchor Point tools, it is no longer possible to adjust the lengths of the handles of a smooth node independently.

    You can use Alt and drag a handle independently and Shift to constrain it.
    ~Fred
    You can drag the handles of a cusp node independently, not a smooth node.

    When you use alt drag, the node is no longer a smooth node. The angles of the handles are no longer constrained to be 180 degrees apart. Once you create a smooth node with the Convert Anchor Point tool, you are forced to convert the node back to a cusp node if you want to adjust the lengths of the handles independently. When you do so, not only are the lengths independent of each other, but the angles as well. It is no longer a smooth node.

    When you use the Shift key to constrain the angles, you are constraining the angle of the handle to be multiples of 45 degrees. You are not constraining the angles of the two handles to be 180 degrees apart from each other as is the case with a smooth node.

    Try this.
    Create a new curve with with 3 nodes by clicking and dragging with the Pen tool at 3 different points on the artboard. Now try adjusting the handles of the middle node with the Direct Selection tool. Notice that this is a smooth node and you can also adjust the lengths (but not the angles) of the handles independently. The node is smooth and asymmetrical.
    Now click and drag the middle node with the Convert Anchor Point tool. Notice you can no longer adjust the lengths of the handles independently with the Direct Selection tool. Adjusting the length of one handle also adjusts the length of the other. The node is smooth and symmetrical. You cannot revert back to smooth and asymmetrical. The only way to adjust the length of the handles of the node independently from this point on is to convert to a cusp node.
    Monday, December 19, 2011 2:58 PM