# 3D Animation, Objects: Boolean operations: Tuerca [Blogs experimental] [ Blender ]

The Boolean operations to model objects from a set of basic primitives to which are applied addition operators, difference and intersection.

Tuerca

The mechanics are simple objects obtained with this technique, and that “manufactured” also from the “basic forms”.

A simple example is a nut; apparently seems to contain a large number of curves on its surface that are complex to manually generate, namely, editing point to point each.

These lines are machined product having a bar of metal material to form the nut.

We can simulate a manufacturing process in which we start from a volume to which we add or remove other volumes, obtaining an envelope surface whose curves are formed by the intersections of the objects involved.

Esteejemplo has been developed for release 2.49, for higher versions type 2.64 consult him on 2.6x theme modifiers:

Modifiers : Booleans in Blender 2.6

# Modeling a Nut

A nut is obtained by applying two Boolean, the difference and intersection. Previously need a solid “mechanize” with these two operations.

## Nut solid base

A circle is the primitive that allows for regular polygons; will control the number of vertices to determine the number of sides of the polygon that approximates.

To start building the model we can start from a polygonal shape with six sides or faces for obtaining a regular prism.

First add the polygon with Add->Mesh->Circle as we have to add an object Blender. Polygonal face select and enter the “edit mode” to generate a sound from it.

From hexagon and by edited by extrusion of this face (we press “And“), a prism that is obtained is the basic form and in turn the convex border of the nut.

Anywhere in the nut is found inside this volume; also serves to a simplified representation of the object, because it determines its apparent contour when projected.

Another alternative would have been based on a six cylinder in the circular faces vertices. We have saved the extrusion, but the didactic article is bundled with this scheme.

## Modeling with Boolean operations

Then modify the solid applying boolean operations necessary.

Together with the hole required to insert the screw, Real nut presents a “recesses” or fillets on the edges very characteristic. The end of said recesses is to facilitate self-centering of the tool you'll use for your press.

First proceed to obtain these “recesses” and subsequently “perforaremos” the object completing the simplified basic model we want for our animation.

The interior of the nut should be threaded whether to display, although in most cases, being in contact with the screw, can be obviated thereby simplifying the model. In our case we will not, leaving for another article this specific detail is more complex.

To complete the outer appearance of the nut need a cone of revolution sustraeremos the prism.

To incorporate the cone place the cursor in the 3D window and we will press the spacebar to access pop-up menus. Therefore select:

in corresponding menus displayed. Although we make two recess operations (one top plate and one in the lower) with a single cone can get both.

### Intersection Operator

The first operator to determine the intersection will use solids.

First will place the cone on the prism (nut) as seen in Figure, so that they are out “corners” upper prism.

Then determine a new solid formed by “the common” both elements (prism and cone), making the material located outside the cone will be removed.

To determine “the common” or intersection of the two solids must select both, with any of the methods we have seen for select objects and edit screens. For example, pressing “shift” and pressing the Right mouse on each of the objects, or pressing “B” and setting a rectangle that contains.

Once selected, and so “object” proceed to implement the Boolean operation “intersection”, pressing “W” we displayed the menu for this type of action.

We will repeat the operation reversing the cone. For this, it we turn 180 grados and will move to obtain a position similar to the previous, as reflected in the image.

This rotation can be done by selecting the cone and then pressing “R” (Rotate) and then the “And” (in our case the green axis represents the axis of the “And”). Required to adjust the angle write “180” and will press “return” or will use the dialog box you get when you press “N” and to enter the corresponding offset values, scale and rotation of the object.

When performing any operation generates a new sound keeping the originals that must be removed later.

### Difference Operator

The last operation will get a hole that will serve to introduce the screw on the object “nut” we are doing.

When the operation has allowed to determine the intersection, the first step was to select items. In this case no matter what the order of selection, however, operation “Difference” required to establish an order to identify what is the primary and which object will use to “deduct”.

The first selected object will act as the main element, while the second part of the volume determined to remove or delete.

Therefore select the nut first and then the cylinder which determine the hole.

Then, and similarly to previous steps, press the key “W” to get the pop-up context menu that enables solid operations. In this case the operator will select the corresponding “Difference“.

## Result

Once sections deleted or the original objects of the scene, we can see the new item generated as a result of the Boolean operations performed.

Only missing generate internal thread as mentioned leave for a more advanced tutorial.

The last step is to assign or add the material to the object to simulate its appearance “metal”.

Poco a reflection of how we attribute the main approach to correct visualization su, so you have to activate the “Ray tracing” if we approach al visual realism.

Como ejemplo, We can assemble a small scene and create an animation with our nut and screw cylinder simulating.

For the example shown below has added a base plane to the above mentioned, and a pair of lighting points.

The result you get may be something like this, although much will depend on the lighting, the camera position, the number of frames and animation “key frames” we have defined.

Did you find interesting the result?.

It is simple, even necessary to exercise in the conceptualization of an object as a composition (sum, subtraction and difference) of simpler. Quite a constructivist philosophy.

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