View Full Version : Relative position connection

01 January 2007, 12:36 AM
Here is my problem, Ive got a spline with, let say 9 points, I use a Point IK on it between point 0 and 7. Now I want the two points after that 8 and 9 to stick to the IK goal but KEEP there current relative positions to the IK goal.

I solved this by assigning point 8 and 9 one selection tag each and connected them to nulls with xpresso then I parented the nulls to the Point IK goal, so far all is good.

The problem comes when I want to use phytools flex on the spline, it dosent seem to work with that approach. So the big question is how do I connect point 8 and 9 to the IK goal and keep there relative position directly in xpresso. I have a feeling that I use a similar setup to my current one, but instead of putting nulls in the pointnodes pointposition port I put the IK goal position.

But first I have to alter it some way so that they keep there distance in space to the IK goal but still follow it.

Any help would be very appriciated.

01 January 2007, 09:29 AM
Here's a basic XPresso setup for offsetting 2 points relative to another object. User Data on the XPresso tag allow you to manually enter point offsets relative to the goal. I tried an expression using a COFFEE node and another using Freeze nodes. Each allowed point offsets to be automatically frozen but in both cases the spline was corrupted after closing and reopening the file, so I had to revert to this sub-deluxe approach.

Dropping an object into the link box or changing point index settings for a linked object will alter point positions. These changes cannot be undone. Changes to the User Data point offset values can be undone. The best approach is to make sure that indices of points to be offset are correctly selected in the User Data before dropping the spline into the link box. Their offsets can then be interactively adjusted.

01 January 2007, 11:13 AM
Big thanks:thumbsup:

Not only does this help me with my problem, it will also gives me some help with understanding some of the xpresso nodes better. I will post a animation test once Ive finished.

Thanks again!!!

01 January 2007, 11:32 AM
Glad that you've found it helpful.

The MatrixMulVector node is very useful and easier to understand than its name might suggest. The manual gives a clear, concise explanation. You'll wonder how you ever managed without it.

01 January 2007, 12:45 PM
For stuff like this also check the Xpresso Matrix presets in the X-Pool

01 January 2007, 01:06 PM
Thanks Srek.

Im new to xpresso so your tips are very wellcome.:thumbsup:

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01 January 2007, 01:06 PM
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