T-Spline Merge Edge Location Issue

[LukasKaiser]

Hi, if somebody help me with this I will be very pleased.

1) These are two identical T-Spline Panel Squares.

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2) Each side is 25cm

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3)Also gap between them is 25cm

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4)I want green edges to merge with purple ones. But while I'm doing this. I want purple edges to stay where ever they are. I only want green edges to move.

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5)So I used "Merge Edge" option. (Later, I tried lots of modify options like "weld vertices".).

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6) Side number one is 25cm. It is Good.

But side two is 29.167cm. NO! This is NOT what I wanted. I want side two to remain 25cm. Only side three and side four can change.

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7) So somehow I need the ground purple square, then make "Merge Edge"

I do not want to make some handy work after the process like insert edge, move edge, etc...

Because sometimes it is become difficult to do it with your hand.

Also I do not want to make them component first. 

Because when I do that. I can't edit the form again.

[laughingcreek · Accepted solution]

T-spline forms aren't intended to be manipulated in the way your proposing.  Just not how the tools are built.  Honestly there general isn't a need for it any way because those lines are just visual representations of the underlying control points.  Sort of like a control point spline expanded into surfaces.   When you start thinking about them they way you are now, you end up chasing our tail, as your discovering.

maybe if you take a step back and describe/show what you want to achieve someone can help with a good method.

[jeff_strater · Accepted solution]

@laughingcreek is correct.  This is not an expectation you should have for T-Splines.  The thing you should know about T-Splines is that when you are moving edges/vertices, you are really manipulating a control frame.  You can see this control frame by turning on Box mode:

When you move this control frame, T-Splines applies a smoothing algorithm which produces the smoothed shape.  In that process, edges or vertices can move from their position in Box mode.  This is expected, and is necessary for the smoothing to succeed.

A question is:  what are you designing, and why are you choosing T-Splines to do this?  There may be other ways to model it.

[LukasKaiser]

Actually I found the correct method to do what I want. I was just looking for a second way to do this. Because learning new things are good:) Now I know this method is not correct. Thank you all.