Seam
Seam brings any two sequences of edges of your object together, deforming the surrounding geometry to match the movement of your chosen edges.
To use Seam you'll need to start with a polygon object, then make two separate edge selection tags (each one a single line of continuous edges), add those selection tags to Seam's 'Edge selection' fields, and then tweak the settings until you get the effect you're after.
The image above shows the edge selections that went into making this particular Seam effect.
From the original object, the Seam can be animated closed in a number of ways using the 'Strength over length' curve.
Options
- Edge selection 1 - link the edge selection tag of your first edge here.
- Reverse edge 1 - Seam will internally create a linked sequence of points based on your edge selection tag, but depending on the order of that sequence your edges can get crossed over. Check this option to reverse the sequence to fix those problems.
- Edge selection 2 - link the edge selection tag of your second edge here.
- Reverse edge 2 - see 'Reverse edge 1'
- Match points - if each edge has the same number of points, at 100% strength Seam will connect the corresponding points from each edge in order (this often gives nicer geometry and is useful if you'd like to use 'Connect' on the resulting geometry). If 'Match points' is turned off or your edges have a different number of points, the points will instead be moved towards the other edge based on their distance along their edge.
- Edge weight - at 50% both edges move towards each other equally, at higher or lower values one edge will move less while the other moves more to compensate.
Strength:
- Strength - the overall strength multiplier, with no 'Strength over length' curve your edges will meet when 'Strength' is at 100%. You can set this to a negative value to move the edges away from each other.
- Strength over length - this curve modifies the strength of the Seam effect over the length of the edges, you can animate this curve to achieve a range of effects (eg zipping).
Falloff:
Don't confuse these Falloff settings with those in the Falloff tab, these ones control how the rest of your geometry should be deformed to match the deformation of your selected edges.
- Distance - the maximum distance from the selected edges within which points will be moved to match the movement of your edges.
- Falloff - use this curve to control the strength of the deformation applied to those other points depending on their distance from the selected edges. The default (if no curve is defined) is a linear falloff.