Creating Revit families – Basic 3D modeling tools explained
To round up the beginners family series, before I move on to some more advanced geometry and adaptive components, I will explain all of the 3D modeling tools available in the Revit Family environment and display some of the different uses for each tool along with an image as an example of each method / tool available in Revit. (Sorry about the Marble finish I have set as my generic model material ;))
The Extrusion tool is most likely the first 3D modeling tool you played around with in Revit. It is used to create simple forms such as the cube shown to the right. It is possible to give the geometry a 2D profile which will then extrude with a thickness depending on what options you have set in the ‘extrusion start’ and ‘extrusion end’ properties. It is possible to drive the dimension either with parameters or by locking and flexing the grid.
The Blend tool is another of the common tools used in the family environment. It is created, simply by specifying a base and a top profile. Revit will then join the geometry between these 2 profiles, with a specific extrusion depth. It is also possible to change and control these forms with parameters and reference planes. Useful for creating cone / funnel shaped forms but also any form thats width varies throughout the length of the geometry.
The revolve tool creates a solid form revolving around a user defined axis line. A 2D profile is drawn to represent the form of the geometry. Due to the fact the an axis line is used, we only need to draw half of the desired geometry and the axis / revolve line will act as a mirror. You can then set the revolve radius, by default it’s set to 360* which will give a full revolve, in the image I have created a 320* revolve radius which then leaves an opening.
The Sweep tool is very useful for creating swept geometry which follows a defined path, for example a pipe or structural beam could be drawn using this method. Other uses are for example drawing a door frame which follows a path with exactly the same profile all the way around. Firstly you have to draw your path (often on an elevation view) and then draw your profile (on a plan view). Sweeps can also be made parametric for editing dimensions.
The Swept Blend tool is as the name suggests, a mix between a sweep and a blend. This tool is used for creating a sweep with a different start and end profile. It therefore creates a sweep driven by the path sketch, and then defined by the start and end profile of the blend. To the right is a very simple example of a swept blend but they can be used to create much more detailed and abstract geometry for example a lamp post or a curved wall mass.
The Void Extrusion tool is a part of the void modelng forms toolset in Revit. For each instance of modeling tool, there is also a void tool which can either be used alongside or independtly to the extruding 3D tools.. It is an essential tool for 3D modeling, and again, as the name suggests, it creates a void in an extrusion as shown in the image to the left. This tool can be used to hollow out or create openings in solid extrusions.
The Void Revolve tool is the final 3D modeling tool I will be discussing, as it is clear what all the void tools are used for and what can be achieved by using them. As you can see to the right, this tool can create some interesting shapes and forms. When used in conjunction with the revolve tool it can create hollowed out shapes. It is also possible to use these void forms. It is created in exactly the same way as the revolve tool, and you could say, has the exact opposite effect. Removing rather than adding geometry.