VW version 12.3.5 oval offset

[sphere3d]

When i try to offset an ellips (made by ellipse by box tool) which has been rotated, it seems the duplicate is not excact a smaller version of the original.... it looks like an alien....how to overcome?

Robert

Edited January 27, 2010 by sphere3d

[michaelk]

Setting aside the when-is-it-an-oval-and-when-is-it-an-ellipse discussion for a second...

And ignoring the rotation issue...

I have noticed (in VW 2010) that the offset tool, when applied to the inside of an oval/ellipse, shrinks the semi-major axis slightly more than the offset value. The major axis shrinks the expected amount.

When applied to the outside of the oval, both the semi-major and major axes have the expected values.

That may be what you are seeing...

This might be one way to overcome: Temporarily rotate the oval horizontal, duplicate, enter the new height and width values in the OIP, rotate back...

michaelk

[sphere3d]

Well, setting aside when-it-is-an-oval-and--- discussion:

Still the problem remains when the offsettool is used on a rotated oval, i will not get a smaller rotated oval but a polyline (some are bezier, some are spline based) with a wierd shape.

So why is this? And using values is nice, but needs calculation....

Anyone from Nemetschek??

Robert

[michaelk]

That may be a version 12 thing. In 2010 the offset of an oval is always an oval.

michaelk

[MullinRJ]

In VW 12, rotation of Rectangles and Ovals always creates a Polygons and Polylines, respectively. So, before you use the Offset tool, you are working with an approximation of the Oval made of Bezier segments. Rectangle and Oval rotation wasn't fully implemented until VW 13 (2008)

Raymond