SetOpacity

Animate transparency on a whole protein or a selected region.

from proteinmotion import SetOpacity

Constructor

SetOpacity(target, opacity, **kwargs)

Parameters

Parameter	Default	Description
`target`	Required	Protein or Region to style.
`opacity`	Required	Opacity in [0, 1], from transparent to opaque.
`**kwargs`	—	Additional keyword options described below or in the linked constructor.

Additional keyword arguments

Parameter	Default	Description
`residue_delay`keyword only	`0`	Delay in seconds between successive residue starts.
`reverse`keyword only	`False`	Reverse residue or glyph order.
`easing`keyword only	`'smooth'`	Per-residue interpolation: "smooth" or "linear".

Notes

Residues start in topology order from N to C. run_time must exceed (residue count − 1) × residue_delay. Use easing for each residue transition; the clip clock stays linear. Disjoint atom selections can animate together.

Example and output

This excerpt runs inside a scene’s construct() method. The full example file includes imports, structure loading, and camera setup. Run it from a repository checkout.

Code Scene excerpt

p = ubiquitin().ball_and_stick()
helix = p.select(residues=(23, 34))
helix.set_color("#50e0d0")
frame(self, p)
self.wait(0.5)
self.play(
    SetOpacity(helix, 0.1, residue_delay=0.06),
    run_time=2,
)
self.wait(0.7)
self.play(SetOpacity(helix, 1), run_time=1.5)
self.wait(0.5)

Output Preview · 5.2 s · 60 fps

Residue transparency

The selected helix fades and returns.

Full source: Opacity Download MP4

Methods and properties

Name	Description
bind()method · inherited from _AppearanceAnimation	Capture starting values when the scene schedules the animation.
apply()method · inherited from _AppearanceAnimation	Evaluate the animation at eased progress alpha. Called by the timeline.
targetsproperty · inherited from Animation	Objects whose state this animation changes.