Tag Archives: metaball

Nov 12 2014

Magnet SOP tutorial.

The Magnet SOP. TouchDesigner 088. 2014.
The Magnet SOP can be used to deform Surface Operators. It can be hard to understand and master, but it can help you produce some difficult to achieve effects.

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Let’s examine the magnet SOP.

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The magnet SOP is an extremely
powerful operator in Touch
Designer, but it can also be
difficult to understand and
implement properly.

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A magnet SOP must work in
conjunction a metaball,

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and the relationship between the
metaball and the magnet will
determine the nature of the
effect generated by the magnet
SOP.

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In this example we will deform a
sphere SOP with a magnet SOP.

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The transform parameters of the
metaball SOP are the primary
influences used to drive the
effectiveness of the magnet SOP.

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The core operators in this
tutorial network are the sphere,
metaball, and magnet.

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The additional operators are
simply for visualization
purposes.

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We want to see the effect the
magnet has on the input sphere,
and at the same time, see the
metalball which is driving the
effect.

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I’ve wired the outputs of the
magnet and the metaball to point
SOPs, and changed their display
parameters.

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I’ve changed their colors, and
reduced their alphas, so that
when we render the SOPs we can
see them as they overlap.

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I’ve created a TOP network
starting with a render TOP.

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I’ve added a camera and a light,
as well as an over TOP, so we
can place the render on a white
background.

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It can be challenging to locate
and visualize objects in 3d
space.

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By adjusting the parameters of
this network, we can keep track
of the effects of the magnet
SOP.

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I use a slider component to
uniformly adjust the scale of
the metaball in 3 dimensions.

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As I boost the scale, we can
immediately see the effect of
the magnet.

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The magnet, which is effectively
the input sphere, is green. The
metaball is purple.

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The relationship between the
transforms of the magnet and
metaball create the deformations
of the input sphere.

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As with a physical magnet, the
input geometry can be partially
or completely transformed.

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For the magnet SOP to work, the
relationship between the magnet
and metaball must be at least
slightly offset.

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As you can see, adjusting this
offset in either the metaball or
the magnet, will create
variations of the magnet’s
deformation of the input sphere.

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As I adjust the offset of the
magnet, the metaball scale will
cause the input sphere to be
deformed in the direction of the
magnet.

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A transform X offset of positive
.1 will cause the sphere to move
or deform to the right.

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An offset of 0 will have no
effect, as there is no
relational offset between the
magnet and metaball.

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The smaller the offset, the
smaller the effect.

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