Stair Grasshopper Styles Tutorial

Comparison between the Grasshopper stair on the left and the VisualARQ stair on the right.

In this tutorial a parametric stair style from a Grasshopper definition will be created.

The 3 main steps to follow are the same as in any other Grasshopper style:

  1. Grasshopper definition setup
  2. Create the VisualARQ stair style
  3. Insert and edit a VisualARQ stair created from a Grasshopper style

1. Grasshopper definition setup

You can download the complete Grasshopper file clicking here.

Type Grasshopper in the Rhino Command line to launch Grasshopper.

  1. Input parameters components:

    They define the values of the resulting stair style. In this example we can find the following kind of input parameters:

    • Value list: for the three options of the stair alignment: right, center and left. Each one corresponds to an integer value.
    • Number Slider (floating point): a total of 5 sliders have been used for the various dimensions of the stair.
    • Number Slider (integer): they specify the amount of steps.
  2. Output components:

    They are the “ending” components. They need to be Geometry Params that are no further connected to any other components. They will be read by VisualARQ as the different parts of the stair style. In this example there are two Geometry Params: one for the upper plates and one for the lower plates.

The complete Grasshopper definition is shown in the image below:

The stair Grasshopper style definition. On the left the various input parameters and on the right the geometry components as output.

The Grasshopper definition that generates the stair.


2. Create the VisualARQ stair style

In this case the Grasshopper style will be created and managed from the Stair Styles Properties dialog.

2.1: Create the new style

Assuming the Grasshopper definition (.gh file) is already done, open the stair styles dialog: _vaStairStyles.

Click on the New… button and select the Grasshopper style option.

The stair styles dialog with the "Grasshopper style" option visible after clicking on the "New..." button.

The Grasshopper Style wizard will appear. This wizard will guide you through the steps to define the stair Grasshopper style parameters. The left side of the wizard will show a preview of the object style generated as soon as the required information is completed.

2.2: Open the Grasshopper definition

Click on the Browse button to select the .gh file created before.

First step of the Stair Grasshopper Style Wizard. In this step the Grasshopper file is selected.

2.3: Configuration

Set the Stair Grasshopper style global values:

  • Style name: set the desired name.
  • Definition units: in this case the Grasshopper definition was created in meters.
Second step of the Stair Grasshopper Style Wizard. In this step the name and the units are selected.

2.4: Geometry

Specify which of the geometry blocks to import into VisualARQ. The identifiers of these Geometry blocks are taken from the names of the output components in the Grasshopper definition and can be modified only once the style has been created.

Each component can be assigned to a different representation:

  • Model: the object representation in 3D.
  • Plan: the object representation in plan view. Only visible when the Cut Plane of the level where the object is placed is enabled and intersects the element.

In this case there are two geometry outputs that correspond to the Model representation. The Plan representation will be taken from the horizontal section of the 3D elements according to the level’s cut plane height.

Third step of the Stair Grasshopper Style Wizard. In this step the geometry to be displayed and its representation is chosen.

2.5: Parameters

This step shows the settings available for the list of input parameters that define the stair style. The “Filter by” dropdown can be used to view individually each of the named groups of input parameters that were created in the Grasshopper file. The settings available for each of the inputs are:

Name: is the identifier of the parameter and can be modified if desired in this step.

Editable by:

  • Definition: the parameter will be hidden in the VisualARQ style and properties dialog.
  • Style: the parameter can be edited by style, so the changes will apply to all elements with that style.
  • Object: in this case this option will be selected for some of the parameters so they can be edited separately for each instance of that style in the model. In case no value is provided by object the one defined by style will be used.

You can change the settings of different parameters at once by selecting them while holding the Ctrl key.

Fourth step of the Stair Grasshopper Style Wizard. In this step the four settings are the "Name", the "Editable by", the "Default" (value) and the "Type".

Default (value): shows the default value for the parameters (the ones specified in the Grasshopper definition) and lets you set different default values.

Type: shows the different types of values available for each kind of parameter. In this case almost all of them are floating point values that automatically have been set to Length and there are also two Integer values.


3. Insert and edit a VisualARQ stair created from the Grasshopper Stair Style

3.1 Edit the stair style

Once the Grasshopper style wizard is completed, the new style will appear in the stair styles list with its corresponding sub-components (Upper plates and Lower plates). To edit the style again, right-click on the style name to open the context menu and select Edit. This operation will open the Grasshopper style wizard again. The parameters are available under the “Parameters” tab and appear grouped as in the Grasshopper definition. In case the name of the group matches an existing category they will appear combined.

The Stair styles dialog with the new stair style. When it is selected the parameters appear under the "Parameters" section grouped as in the Grasshopper definition.

3.2 Insert the Grasshopper style

Once the stair style has been created, you will be able to insert an instance in the document. You will be able to change the values of its parameters from the VisualARQ stair icon located under the Properties panel. Only those input parameters that were set as editable “by Object” in the step 2.5 will be visible.

Example of a stair with the new style. Some of the input parameters appear in the Properties panel since they have been set as editable by object.

Note: the features and edit options of this stair object created from Grasshopper differs from the standard VisualARQ stair object. That means that certain options such as the edition of the stair flights or the slope rule are not available on this stair.