This is another helper that can superimpose shapes representing information from a number of different model components which may represent different types of object and have different array dimensions. In this case, a set of model components can be used to provide data for a shape or group of shapes in a 3-D scene. For instance in this representation of a plant, a sphere is used to show the root volume, cylinders are used to show the leaf stems (petioles) and ellipses are used to show the leaves themselves.

When the helper is first invoked, the grid is displayed showing X axis indices in red, Y in blue and Z in black. There are currently three types of shape which can be added. The dimensions of all model values used to create each set of shapes must be the same. To add a set of shapes, select the type using the menu button at the bottom. You will then be prompted to specify how the shape corresponding to each model instance will be drawn.

The controllable aspects of the shape include its geometry, specified as one or more sets of X, Y and Z coordinates, possibly its size or thickness specified as a single value, and one or more colours. Each of these aspects can be set to correspond to a model value (by clicking its component), or given a fixed value in the helper (by entering the number). In the case of colours, a value for all that group of shapes can be selected using a standard colour selection dialogue, so shapes in that set will have the same colour(s). Alternatively, the colours can be set like the geometry, according to the values of a model component. If this is done, the standard dialogue for creating a colour legend is displayed, so the modeller can specify how the model values map onto displayed colours. Note that for this tool there is currently no opportunity to set the range of values covered by the colour legend; it is always from zero to the number of swatches (which can be up to 255).

When the selections are complete, the shapes will be added to the display.

This is the simplest type. It requires model components representing the X, Y and Z coordinates of the sphere centres, and one for the radii of the spheres. The colour must also be specified.

This requires seven model components, representing the X, Y and Z co-ordinates of the start and end of the line, plus one representing the line thickness. The colour must also be specified.

This requires eight model components. The first three are the X, Y and Z co-ordinates of the ellipse centre. Then there is one for the radius of the ellipse along the X (major) axis, and one for the eccentricity, which is the factor by which the Y axis radius is smaller. The ellipse will be drawn parallel to the XY plane if the next two are zero. The first of these is the rotation about the X axis, which rolls the ellipse around the major axis. Then comes rotation about the Y axis, which tilts it around the minor axis. The last one is rotation around the Z axis, which revolves the ellipse in its plane. Note that each rotation also rotates the axes for subsequent rotations. In addition to the geometry, two colours must be specified for ellipses, the first for the front (initially upper) surface, the second for the back.

The view in the shape viewer can be adjusted using the mouse. The camera can be swivelled around the centre of the view by left-dragging in the view window, and zoomed in and out using the scroll wheel. Right-dragging will cause the camera to move perpendicularly to the direction in which it is looking.

In: Contents >> Running models >> Working with helpers

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