Documentation 
Rigid solid with geometry, inertia, and color
This block represents a rigid solid with geometry, inertia, and color. The solid 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 Solid and Rigid Transform blocks to model a compound rigid body.
Geometry parameters include shape and size. You can choose from a list of preset shapes or import a custom shape from an external file in STL or STEP format. The block can automatically compute the inertial properties of the solid based on the geometry you specify given its mass or mass density.
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 a solid shape. The table summarizes the various shapes that you can select. The default shape is Brick.
Shape  Description  Example 

Cylinder  Cylindrical shape with geometry center at the reference frame origin and symmetry axis aligned with reference frame Z axis 

Sphere  Spherical shape with geometry center at the reference frame origin. 

Brick  Prismatic shape with geometry center at the reference frame origin and faces normal to X, Y, Z axes. 

Ellipsoid  3D extension of ellipse with geometry center at the reference frame origin and semiprincipal axes aligned with reference frame X, Y, Z axes. 

Regular Extrusion  3D sweep of regular polygon crosssection along an extrusion axis. Shape has geometry center at the reference frame origin, and extrusion axis aligned with reference frame Z axis. Crosssection is constant along extrusion length. 

General Extrusion  3D sweep of general crosssection shape along an extrusion axis. Reference frame origin coincides with crosssection (0,0) coordinate, halfway along extrusion length. Reference frame Z axis aligns with extrusion axis. Crosssection lies in reference frame XY plane. Crosssection shape and dimensions are constant along extrusion length. 

Revolution  3D sweep of general crosssection about a revolution axis. Reference frame origin coincides with crosssection (0,0) coordinate. Reference frame Z axis aligns with revolution axis. Crosssection lies in reference frame XZ plane. Revolutions can be full (revolution angle = 360°) or partial (0°<revolution angle<360°). For partial revolutions, the reference frame X axis splits the revolution into two symmetric halves. 

From File  3D shape loaded from STL (Standard Tessellation Language)
or STEP (Standard for the Exchange of Product Data) file. The reference frame has the origin and orientation defined in the file. 

Enter the cylinder radius. This is the distance between the origin and circumference of the transverse crosssection. The default value is 1. Select or enter a physical unit. The default is m.
Enter the cylinder length. This is the distance between the two flat surfaces measured along the symmetry axis. The default value is 1. Select or enter a physical unit. The default is m.
Enter the spherical radius. This is the distance between the origin and surface of the sphere. The default value is 1.
Enter a three element vector [a b c] with the brick dimensions along the reference frame X, Y, and Z axes, respectively. The default vector is [1 1 1]. Select a physical unit. The default unit is m.
Enter a three element vector [a b c] with the ellipsoid semiprincipal axes along the reference frame X, Y, and Z axes, respectively. The default vector is [1 1 1]. Select a physical unit. The default unit is m.
Enter the number of sides for the polygonal crosssection. The minimum number of sides is 3. The default value is 3.
Enter the radius of the smallest circle required to completely enclose the polygonal crosssection. This is equal to the distance from the polygon center to the intersection of any two polygon edges. The default value is 1. Select a physical unit. The default unit is m.
Enter the extrusion length. This is the distance along which to sweep the 2D crosssection. The default value is 1. Select a physical unit. The default unit is m.
Enter the crosssection coordinate matrix. This is a matrix with N rows, each with the [X Y] coordinates of a single crosssection point. Coordinates must define a single closed loop. The loop must not selfintersect. The closed loop divides dense and empty regions according to the following rule: as viewed at each point along the crosssection, the dense region lies to the left of the crosssection segment, while the empty region lies to the right. Select a physical unit. The default unit is m.
Enter the extrusion length. This is the distance along which to sweep the 2D crosssection. The default value is 1. Select a physical unit. The default unit is m.
Enter the crosssection coordinate matrix. This is a matrix with N rows, each with the [X Z] coordinates of a single crosssection point. Coordinates must define a closed loop. The loop must not selfintersect. Xcoordinate values must be greater than or equal to zero. The closed loop divides dense and empty regions according to the following rule: as viewed at each point along the crosssection, the dense region lies to the left of the crosssection segment, while the empty region lies to the right. Select a physical unit. The default unit is m.
Specify the angle to revolve the crosssection through. Select Full for a 360 degree revolution. Select Custom and enter a revolution angle for partial revolutions. The revolution angle must lie between 0 and 360 degrees.
Select the format of the source file with the solid geometry data. Formats include STL and STEP.
STL (Standard Tessellation Language) files represent the surface geometry of a 3D solid as a matrix of 2D triangular elements. A normal vector and three vertex coordinate sets, included in the STL file, fully define each triangular element in the tessellated surface. Selecting STL exposes an additional option, Units.
STEP (Standard for the Exchange of Product Data) files represent the surface geometry of a 3D solid using a set of analytical curves. These files can include additional information about a solid, such mass density and physical units.
The block provides automatic inertia computation from geometry only for STEPderived geometries. For STLderived geometries, you must manually enter the solid inertia parameters.
Enter the name of the geometry source file. The name must include the file path, provided relative to the working directory.
Select or enter the desired unit of length. The default is m. This option appears when you select STL as the geometry source file type.
Select a method to specify the inertial properties of the solid. The default is Calculate from Geometry.
Type  Description 

Calculate from Geometry  Automatically compute moments and products of inertia based on solid geometry and either mass or density. 
Point Mass  Treat the solid as an idealized mass occupying an infinitely small volume in space. The inertia tensor about the center of mass is always zero for a point mass. The position of the point mass coincides with the origin of the reference port frame. Select the Point Mass method to represent a simple mass disturbance on a rigid body. 
Custom  Manually specify the inertial properties of the solid, including moments and products of inertia as well as center of mass. 
Select the quantity to base inertia calculations on. Options are Density and Mass. Depending on the method you choose, enter the average mass density or the total mass of the solid. Select a physical unit.
Enter the total mass of the solid. Select a physical unit. The default is 1 Kg.
Enter the center of mass coordinates with respect to the solid reference frame in the order [X Y Z]. In a uniform gravitational field, the center of mass coincides with the center of gravity. Select a physical unit. The default is [0 0 0].
Enter the mass moments of inertia of the solid element in the order [I_{xx}, I_{yy}, I_{zz}]. Each moment of inertia must refer to a frame whose axes are parallel to the block reference frame axes and whose origin is coincident with the solid center of mass. The moments of inertia are the diagonal elements of the solid inertia tensor,
$$\left(\begin{array}{ccc}{I}_{xx}& & \\ & {I}_{yy}& \\ & & {I}_{zz}\end{array}\right),$$
where:
$${I}_{xx}={\displaystyle \underset{V}{\int}\left({y}^{2}+{z}^{2}\right)\text{\hspace{0.17em}}dm}$$
$${I}_{yy}={\displaystyle \underset{V}{\int}\left({x}^{2}+{z}^{2}\right)\text{\hspace{0.17em}}dm}$$
$${I}_{zz}={\displaystyle \underset{V}{\int}\left({x}^{2}+{y}^{2}\right)\text{\hspace{0.17em}}dm}$$
Select a physical unit. The default is [1 1 1] kg*m^2.
Enter the mass products of inertia of the solid element in the order [I_{yz}, I_{zx}, I_{xy}]. Each product of inertia must refer to a frame whose axes are parallel to the block reference frame axes and whose origin is coincident with the solid center of mass. The products of inertia are the offdiagonal elements of the solid inertia tensor,
$$\left(\begin{array}{ccc}& {I}_{xy}& {I}_{zx}\\ {I}_{xy}& & {I}_{yz}\\ {I}_{zx}& {I}_{yz}& \end{array}\right),$$
where:
$${I}_{yz}={\displaystyle \underset{V}{\int}yz\text{\hspace{0.17em}}dm}$$
$${I}_{zx}={\displaystyle \underset{V}{\int}zx\text{\hspace{0.17em}}dm}$$
$${I}_{xy}={\displaystyle \underset{V}{\int}xy\text{\hspace{0.17em}}dm}$$
Select a physical unit. The default is [0 0 0] kg*m^2.
Select a method to represent the solid in Mechanics Explorer. The default is From Geometry.
Type  Description 

From Geometry  Shape specified in Geometry section 
Marker  Simple icon such as Sphere, Cube, or Frame 
None  No visualization 
Geometric shape of the graphic marker. Options include Cube, Frame, and Sphere. The default setting is Sphere.
Absolute size of the graphics marker in pixels. Changing the zoom level in the model visualization pane has no effect on the apparent marker size. The default value is 10.
Color specification type. Options include Simple and Advanced. Select Simple to specify the solid color and opacity. Select Advanced to add lighting effects such as specular reflections and light emission.
[R G B] color vector. This vector contains the red (R), green (G), and blue (B) contents of the solid color on a scale of 0–1. The default vector is [0.5 0.5 0.5]. A color picker provides an alternative means of defining the solid color.
Degree to which the solid obscures model components positioned behind it. The opacity value can range from 0 to 1. An opacity of 0 makes the solid completely translucent, while an opacity of 1 makes the solid completely opaque. The default value is 1.0.
[R G B] or [R G B A] diffuse color vector. The diffuse color is the apparent color of the solid under direct white light. The color vector contains the red (R), green (G), and blue (B) contents of the diffuse color on a scale of 0–1. It can include an optional opacity value (A), also on a scale of 0–1. The default vector is [0.5 0.5 0.5].
[R G B] or [R G B A] specular color vector. The specular color is the color of the glossy highlights on the solid surface. The color vector contains the red (R), green (G), and blue (B) contents of the specular color on a scale of 0–1. It can include an optional opacity value (A), also on a scale of 0–1. The default vector is [0.5 0.5 0.5 1.0].
[R G B] or [R G B A] ambient color vector. The ambient color is the apparent color of the solid under indirect ambient light. The color vector contains the red (R), green (G), and blue (B) contents of the ambient color on a scale of 0–1. It can include an optional opacity value (A), also on a scale of 0–1. The default vector is [0.15 0.15 0.15 1.0].
[R G B] or [R G B A] emissive color vector. The emissive color is the color of light generated by the solid. The color vector contains the red (R), green (G), and blue (B) contents of the emissive color on a scale of 0–1. It can include an optional opacity value (A), also on a scale of 0–1. The default vector is [0.0 0.0 0.0 1.0].
Sharpness of the specular highlights on the solid surface. The shininess value can range from 0 to 128. A low shininess value produces large specular highlights with a gradual falloff in intensity. A large shininess value produces small specular highlights with a sharp falloff in intensity. The default value is 75.
So that you can visually check the solid you are modeling, the Solid block dialog box provides a visualization pane. This pane enables you to view the solid shape, color, and reference frame location from various 3D perspectives. You can select a standard view point or rotate, pan, and zoom the solid view. Select the Update Visualization button to view the latest changes to the solid.
Solid Visualization Pane