Restrictions with Blender: Example of a sewing machine

Blender adds functionality to metric and geometric restrictions for defining mechanisms and simulate its movement.

To illustrate the concept of restriction, we will rely on a simple mechanism such as that converts a circular motion to another reciprocating along an axis.

Imagen de Wikipedia

This mechanism is used for example in sewing machines.

The engine must transmit its circular motion to different parts of the system, in some cases simply change the rotation speed while in others the type of motion change.

In the picture shown, obtained in wikipedia, is observed as the needle hits a vertical displacement, while the spool rotates about an axis. Both elements are driven in turn by a single motor and a set of gears and transmission components as being analyzed.

The tab “Constraints” allows us to access restrictions impose our models.

First select the object to which you want to restrict their movement, and then add a constraint block by clicking on the button “Add Constraint“

Add different elements restriction mechanism, as limitations on the orientation and position thereof.

Restrictions can be combined with hierarchical relationships, an element that is “son” In other moves with his father (parent) by applying a transformation.

In particular in this menu find:

• Distance: Limits the maximum and minimum distance to an object
• Scale: Limits the scale of representation
• Rotation: Restricts rotation around a pivot. It is of great interest in mechanisms that simulate the behavior of an organic patella.
• Position: It limits the movement of the object.

For this introduction closed graphically, observe the movement that can move the needle of the sewing machine.

The motor generates a circular motion which is transmitted through a metal rod to the needle holder, and the embroidery, has limited their sliding movement on a shaft that guides. The movement is limited to a single direction (vertical)

The animation control is limited to the drive wheel, the other associated items are moved according to the movement restrictions.

Do you find interesting these restrictions to create mechanisms?

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