Shape Keys (aka Morphing) / Blender
Shape Keys (called Morphing in Verge3D) is a feature which allows you to modify mesh objects in real-time. The most common use case for this feature is creating parametric objects which can change their dimensions, shape, thickness, holes, profiles etc.
See the following demo as an example:
Contents
Setting Up
Blender shape keys are exported by default. Only Relative shape keys
are supported. Please notice that due to hardware constraints, the total
number of active shape keys is limited. Most of the time it's 5 shape
keys for skinned objects and 6 for others (the "Basis" key doesn't count
towards the limit). See this topic
for more information about calculating the limit in more complex cases.
During rendering, the engine selects 6 shape keys with largest
influences ignoring all excessive shape keys.

Animation
To animate shape keys in Verge3D, add keyframes for their Value parameter. The animation of shape keys works exactly the same as for any other animation parameter. You can run you playback at application start or use animation puzzles for that purpose.
Controlling via Puzzles
To manipulate your shape keys in real-time there are two puzzles: get morph factor and set morph factor.
See Also
You may also check out the following video explaining how to work with parametric objects in Verge3D.
Got Questions?
Feel free to ask on the forums!