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View Full Version : Flip parameter central to midpoint of a stretched line



mmccarter
2006-01-11, 10:39 AM
Hello all,

I'm looking at dynamic blocks for the first time this week with a view to creating a library for our medium size land survey company and so I may be missing something fundamental here. Hopefully one of you more experienced dynamic block users will be able to point me in the right direction.

I have managed created a (very!) simple block of a stair arrow symbol which enables the user to easily move and rotate the symbol and extend the "tail" of the arrow all in one move.

The next stage is really as much a learning process for myself more than anything else. I would like to add in a flip parameter so that the arrow head can easily flipped about the centre of the line (which of course is going to change in angle AND length depending on how the stairs are constructed). The problem I am having is that I do not know what to snap to when creating the flip action insertion point. I think that what I need to do select the mid point between the distance parameter as the insertion point, however it seems that I can only select the midpoint of the line itself which obviously is not desirable once the tail of the arrow has been stretched.

Once I manage to solve this problem I will need to make sure that the flip parameter also rotates relative to the orientation of the line after it has been stretched. I will cross this bridge when I get to it as I am a sucker for a challenge.

Any help or input much appreciated in advance,

Matt

Thomas Dean
2006-01-11, 03:13 PM
What you want to do is add another polar stretch to the distance parameter and only include the flip paramter in the selection set. Then put a .5 distance multiplier on this new polar stretch. This will keep the flip action always centered. (see attached)

Thomas

mmccarter
2006-01-11, 03:39 PM
Many thanks,

That is precisely what I was after.
Hopefully now I can get into some more complex DB's now.

mmccarter
2006-01-11, 05:28 PM
One question.
I have been unable to sucessfully recreate the flip to work as intended.

When placing the flip parameter, what do you use as the base point? I am using the midpoint of the line in the arc. I would guess that this is where I am going wrong.

Thomas Dean
2006-01-12, 03:23 PM
Right. Add the flip parameter in and select the midpoint of the line as the start point of the flip. Then with ortho on, pick another point somewhere above the first point. That will point it left towards the arrow. Add a polar strectch with .5 distance multiplier to the flip like in the previous message and you are good to go. One thing I probably left off was to add the flip to the move action that you have in there to keep it moving with the arrow.

Thomas