on 2019-11-04 04:56 PM - edited on 2021-11-26 01:10 PM by Rubia Torres
With the Grasshopper - ARCHICAD Live Connection, you can enhance your BIM model with complex shapes that can not be defined easily with the default ARCHICAD tools. In order to be able to properly represent and document these shapes, while keeping the geometry and BIM information intact and the speed unaffected, we developed the Grasshopper Sweep Object. This article explains what this tool is capable of, and how to use it.
You can get the object from BIMcomponents.com, or you can search for them in the Object Tool Settings dialog Search bar, and download them directly into the embedded library.
This object is designed to be used through the Grasshopper - ARCHICAD Live connection. This means that to use it you will need to be familiar with Grasshopper, and there are several settings in the object that cannot be set in ARCHICAD.
Similar to how Complex Profiled Beams and Columns work in ARCHICAD (or how the sweep command works in other 3D modeling applications), you can use this Object to extrude the geometry of a Complex Profile along a 3D path. The advantage of this tool against Standard Beams and Columns is that the resulting element will be a single entity, and you can describe shapes with it that cannot be defined with the standard tools (e.g. a beam that is curved both horizontally and vertically at the same time, properly mitered connections between each segment, etc.).
The resulting object will be highly parametric: you can control the Building Material, Hotspot visibility, Level of Detail, Visibility of edges, etc.; and it also allows you to control the floor plan representation, which responds to cut plane settings.
There are several parameters in the object that are meant to be controlled through the Object Settings Grasshopper Component:
The rest of the settings are to control the 2D and 3D representation of the Object. Most of these are standard to other ARCHICAD elements, but there are several settings that are specific to this object:
In this example, you will see what are the basics of setting up the Grasshopper Sweep Object. This tutorial will follow the transfer of a simple open curve. You can download this example *.GH file from here.
The file also contains a Simple Polyline that can be broken down and transferred virtually the same way.
To get the exact result you want, it is not enough to just select a path and a profile, it also matters in what direction the profile stands around that axis. Let's see what options you have to control this. In the examples below we will be using an example *.GH definition you can download from here.
If the direction of the profile is consistent all along the path, but, by default, it goes the wrong way, you can rotate the direction of the profile all along the curve at once with a single rotation. Use the "Common Profile Rotation" Parameter in the object to control this. It can be controlled from both ARCHICAD and Grasshopper. The value is an angle in Decimal Degrees (°).
You can also set a custom rotation for each node in your path separately, with the "Profile Rotation at nodes" parameter. This can only be controlled from Grasshopper, and the input should be a flattened list of rotations (in decimal degrees °), with one value for each node. Can be used together with the Common profile rotation parameter, in that case, this rotation is added to the Common Rotation, it doesn't disable it.
In case you have a planar frame at a random angle, setting the rotation might be hard, as the profile always tends to keep itself vertical all along the path. In order to align the default angle of a planar curve easily, you have to be able to handle the plane of the curve as it was the horizontal plane.
The "Top Direction" parameter is a single vector, the defines which way is up. By default, it points upwards, but if you want to align it to a random plane, you can get the Z-vector of that plane in Grasshopper, and set it as the new Top Direction. This way you can align any profile to lay flat in a random plane.
The input is a flattened list of 3 numbers (the XYZ coordinates of a Z vector, as if it was pointing from the origin - the default format of a vector in Grasshopper). It can be used in combination with the other 2 rotation methods. You can visualize this vector in ARCHICAD with the "Show Editable Hotspots in 3D" checkbox, in the Object Settings dialog.
In case you want to sweep along a closed curve, you can use the "Close Path" checkbox in the settings of the object, to connect the first and the last point with a segment. In case the last and the first point are the same after you deconstruct the curve into a list of points, there won't be an additional segment added, only the connection will be amended.
You can control this parameter from both Grasshopper and ARCHICAD.
By default, the 2 ends of the Sweep Object will be cut off perpendicularly to the last segment of the path. If you need it to be cut off at a different angle, you can change the cut angle with the "End Cut 1/2" Parameters.
To set a custom angle, you just have to set these parameters to 'custom', and turn on the "Show Editable Hotspots in 3D" option, to adjust it manually. 2 Disks will appear in the 3D window that will let you set the direction in which the path would go if there was one extra segment at the end. The ends will be cut off as they were connecting to this invisible segment.
You can also control the direction from Grasshopper. You can set the direction by defining the position of this same point through the "StartCutCoord" and "EndCutCoord" Parameters. These are also one-dimensional Array parameters that require a flattened list as an input. They both should include 3 values - the XYZ coordinates of this point - in the following format: X, Y, Z.
"Show Editable hotspots in 3D" is a checkbox parameter in the Sweep Object that makes manual editing of each node possible. It is suggested to keep it turned off, as with an extensive amount of points it can cause significant slow-downs (it is turned off by default). When turned one it will let you:
You can choose between 3 different detail levels to change the complexity of the 3D representation of the Object with the "3D detail Level" Parameter. In 'Full', it displays according to the actual Complex Profile geometry. In 'Simplified', the bounding box of the Complex profile is swept along the path. In 'Axis-line only', there is no profile, only the 3D path is kept as a single 3D line.