# Brick Solid

Solid brick element with geometry, inertia, and color

• Library:
• Simscape / Multibody / Body Elements

## Description

The Brick Solid block is a prismatic shape with geometry center coincident with the reference frame origin and prismatic surfaces normal to the reference frame x, y, and z axes.

The Brick Solid block adds to the attached frame a solid element with geometry, inertia, and color. The brick solid element can be a simple rigid body or part of a compound rigid body—a group of rigidly connected solids, often separated in space through rigid transformations. Combine Brick Solid and other solid blocks with the Rigid Transform blocks to model a compound rigid body.

By default, this block automatically computes the mass properties of the solid. You can change this setting in the Inertia > Type block parameter.

A reference frame encodes the position and orientation of the solid. In the default configuration, the block provides only the reference frame. A frame-creation interface provides the means to define additional frames based on solid geometry features. You access this interface by selecting the Create button in the Frames expandable area.

### Derived Properties

You can view the calculated values of the solid mass properties directly in the block dialog box. Setting the Inertia > Type parameter to `Calculate from Geometry` causes the block to expose a new node, Derived Values. Click the Update button provided under this node to calculate the mass properties and display their values in the fields below the button.

Derived Values Display

### Visualization Pane

The block dialog box contains a collapsible visualization pane. This pane provides instant visual feedback on the solid you are modeling. Use it to find and fix any issues with the shape and color of the solid. You can examine the solid from different perspectives by selecting a standard view or by rotating, panning, and zooming the solid.

Select the Update Visualization button to view the latest changes to the solid geometry in the visualization pane. Select Apply or OK to commit your changes to the solid. Closing the block dialog box without first selecting or causes the block to discard those changes.

Brick Solid Visualization Pane

Right-click the visualization pane to access the visualization context-sensitive menu. This menu provides additional options so that you can change the background color, split the visualization pane into multiple tiles, and modify the view convention from the default +Z up (XY Top) setting.

## Ports

### Frame

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Local reference frame of the brick solid. This frame is fixed with respect to the solid geometry. Connect this port to a frame entity—port, line, or junction—to resolve the placement of the reference frame in a model. For more information, see Working with Frames.

## Parameters

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### Geometry

Lengths of the brick sides along the x-, y-, and z-axes of the solid reference frame. These lengths give, in no specific order, the width, thickness, and height of the brick.

Select Entire Geometry to export the true geometry of the Brick Solid block which can be used for other blocks, such as the Spatial Contact Force block.

#### Dependencies

To enable this option, select Entire Geometry under the Export.

### Inertia

Inertia parameterization to use. Select ```Point Mass``` to model a concentrated mass with negligible rotational inertia. Select `Custom` to model a distributed mass with the specified moments and products of inertia. The default setting, `Calculate from Geometry`, enables the block to automatically calculate the rotational inertia properties from the solid geometry and specified mass or mass density.

Parameter to use in inertia calculation. The block obtains the inertia tensor from the solid geometry and the parameter selected. Use `Density` if the material properties are known. Use `Mass` if the total solid mass if known.

Mass per unit volume of material. The mass density can take on a positive or negative value. Specify a negative mass density to model the effects of a void or cavity in a solid body.

Total mass to attribute to the solid element. This parameter can be positive or negative. Use a negative value to capture the effect of a void or cavity in a compound body (one comprising multiple solids and inertias), being careful to ensure that the mass of the body is on the whole positive.

[x y z] coordinates of the center of mass relative to the block reference frame. The center of mass coincides with the center of gravity in uniform gravitational fields only.

Three-element vector with the [Ixx Iyy Izz] moments of inertia specified relative to a frame with origin at the center of mass and axes parallel to the block reference frame. The moments of inertia are the diagonal elements of the inertia tensor

`$\left(\begin{array}{ccc}{I}_{xx}& & \\ & {I}_{yy}& \\ & & {I}_{zz}\end{array}\right),$`

where:

• ${I}_{xx}=\underset{m}{\int }\left({y}^{2}+{z}^{2}\right)\text{\hspace{0.17em}}dm$

• ${I}_{yy}=\underset{m}{\int }\left({x}^{2}+{z}^{2}\right)\text{\hspace{0.17em}}dm$

• ${I}_{zz}=\underset{m}{\int }\left({x}^{2}+{y}^{2}\right)\text{\hspace{0.17em}}dm$

Three-element vector with the [Iyz Izx Ixy] products of inertia specified relative to a frame with origin at the center of mass and axes parallel to the block reference frame. The products of inertia are the off-diagonal elements of the inertia tensor

`$\left(\begin{array}{ccc}& {I}_{xy}& {I}_{zx}\\ {I}_{xy}& & {I}_{yz}\\ {I}_{zx}& {I}_{yz}& \end{array}\right),$`

where:

• ${I}_{yz}=-\underset{m}{\int }yz\text{\hspace{0.17em}}dm$

• ${I}_{zx}=-\underset{m}{\int }zx\text{\hspace{0.17em}}dm$

• ${I}_{xy}=-\underset{m}{\int }xy\text{\hspace{0.17em}}dm$

Display of the calculated values of the solid mass properties—mass, center of mass, moments of inertia, and products of inertia. Click the Update button to calculate and display the mass properties of the solid. Click this button following any changes to the block parameters to ensure that the displayed values are still current.

The center of mass is resolved in the local reference frame of the solid. The moments and products of inertia are each resolved in the inertia frame of resolution—a frame whose axes are parallel to those of the reference frame but whose origin coincides with the solid center of mass.

#### Dependencies

The option to calculate and display the mass properties is active when the Inertia > Type block parameter is set to ```Calculate from Geometry```.

### Graphic

Choice of graphic to use in the visualization of the solid. The graphic is by default the geometry specified for the solid. Select `Marker` to show instead a simple graphic marker, such as a sphere or cube. Change this parameter to `None` to eliminate this solid altogether from the model visualization.

Shape of the marker by means of which to visualize the solid. The motion of the marker reflects the motion of the solid itself.

Width of the marker in pixels. This width does not scale with zoom level. Note that the apparent size of the marker depends partly on screen resolution, with higher resolutions packing more pixels per unit length, and therefore producing smaller icons.

Parameterizations for specifying visual properties. Select `Simple` to specify diffuse color and opacity. Select `Advanced` to specify more visual properties, such as Specular Color, Ambient Color, Emissive Color, and Shininess.

#### Dependencies

To enable this parameter, set Type to ```From Geometry``` or `Marker`.

RGB color vector with red (R), green (G), and blue (B) color amounts specified on a 0–1 scale. A color picker provides an alternative interactive means of specifying a color. If you change the Visual Properties setting to `Advanced`, the color specified in this parameter becomes the Diffuse Color vector.

#### Dependencies

To enable this parameter, set :

1. Type to `Marker`.

2. Visual Properties to `Simple`.

Graphic opacity, specified as a scalar in the range of 0 to 1. A scalar of 0 corresponds to completely transparent, and a scalar of 1 corresponds to completely opaque.

#### Dependencies

To enable this parameter, set:

1. Type to `Marker`

2. Visual Properties to `Simple`

True color under direct white light specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. An optional fourth element specifies the color opacity also on a scale of 0–1. Omitting the opacity element is equivalent to specifying a value of `1`.

#### Dependencies

To enable this parameter, set :

1. Type to `Marker`.

2. Visual Properties to `Advanced`.

Color of specular highlights, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

#### Dependencies

To enable this parameter, set:

1. Type to `From Geometry` or `Marker`

2. Visual Properties to `Advanced`

Color of shadow areas in diffuse ambient light, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

#### Dependencies

To enable this parameter, set:

1. Type to `From Geometry` or `Marker`

2. Visual Properties to `Advanced`

Graphic color due to self illumination, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element (A) specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

#### Dependencies

To enable this parameter, set:

1. Type to `From Geometry` or `Marker`

2. Visual Properties to `Advanced`

Sharpness of specular light reflections, specified as a scalar number on a 0–128 scale. Increase the shininess value for smaller but sharper highlights. Decrease the value for larger but smoother highlights.

#### Dependencies

To enable this parameter, set:

1. Type to `From Geometry` or `Marker`

2. Visual Properties to `Advanced`

### Frames

Select to expose the R port.

Click the Create button to open a pane for creating a new body-attached frame. In this pane, you can specify the name, origin, and orientation for the frame.

• To name the custom frame, click the text field of the Frame Name parameter. The name identifies the corresponding port on the solid block and in the tree view pane of the Mechanics Explorer.

• To select the Frame Origin of the custom frame, use one of the following methods:

• At Reference Frame Origin: Make the new frame origin coincident with the origin of the reference frame of the solid.

• At Center of Mass: Make the new frame origin coincident with the center of mass of the solid.

• Based on Geometric Feature: Make the new frame origin coincident with the center of the selected feature. Valid features include surfaces, lines, and points. Select a feature from the visualization pane, then click Use Selected Feature to confirm the location of the origin. The name of the origin location appears in the field below this option.

• To define the orientation of the custom frame, under the Frame Axes section, select the Primary Axis and Secondary Axis of the custom frame and then specify their directions.

Use the following methods to select a vector for specifying the directions of the primary and secondary axes. The primary axis is parallel to the selected vector and constrains the remaining two axes to its normal plane. The secondary axis is parallel to the projection of the selected vector onto the normal plane.

• Along Reference Frame Axis: Selects an axis of the reference frame of the solid.

• Along Principal Inertia Axis: Selects an axis of the principal inertia axis of the solid.

• Based on Geometric Feature: Selects the vector associated with the chosen geometry feature of the solid. Valid features include surfaces and lines. The corresponding vector is indicated by a white arrow in the visualization pane. You can select a feature from the visualization pane and then click Use Selected Feature to confirm the selection. The name of the selected feature appears in the field below this option.

Frames that you have created. `N` is a unique identifying number for each custom frame.

• Click the text field to edit the name of an existing custom frame.

• Click the Edit button to edit other aspects of the custom frame, such as origin and axes.

• Click the Delete button to delete the custom frame.

#### Dependencies

To enable this parameter, create a frame by clicking New Frame.

## Version History

Introduced in R2019b