Tutorial: Rhinoceros 4.0 SR8 Date: 14 November 2010 Rhinoceros (Rhino) is a NURBS-based, as opposed to a mesh-based, modeling program, rather similar to Revit. NURBS stands for Non-Uniform Rational Basic Spline, which is just a complicated way of saying that it can produce accurate curves. Mesh modeling on the other hand approximates all curvatures with triangles. Examples of mesh-based modeling software are AutoCAD (2011 does contain some NURBS features), Ecotect, and 3ds Max.
Layout The layout of my version of Rhino will differ from the default layout as I have customized the toolbars.
On the right, I have the layers panel open. This is not open by default, but is probably one of the most important things to always have on. On the top, there is the menu bar, this if usually more helpful for finding the feature you need rather than using the icon in the various tool bars. Below the menu bar is the history list and the command bar. Personally, I feel that using the command bar is the fastest way of modeling in Rhino, but everyone will have their preferences. If you have a lot of experience in AutoCAD, the command bar will be a very familiar feature. However, if most of your modeling experience is in Revit, I would suggest just
using the menus and toolbars. On the bottom, there is tool bar with various information, but at this point, you only need to know about the snaps.
Snaps Snaps are extremely important to use and understand. Not using snaps will lead to very messy models that will evntually force you to remodel the whole file from scratch. Having the wrong snaps on will just make your life frustrating. So, the key with snaps is to only have to ones you need turned on at any given point. There are four types of snaps: snap, ortho, planar, and osnap. Snap will snap your cursor to the grid lines in the viewports. Ortho will snap cursor such that all your points are orthogonal from one another. Planar will snap your cursor so that all your points are on the same plane as each other. Osnap stands for object snap. This will allow you to snap your cursor to existing objects.
Viewports Next, we will talk about the viewports. The default is four viewports: top, perspective, front, and right. If you right-click on the viewport title and click maximize, that viewport will become the only visible viewport. Once the viewport is maximized, you can right-click on the title again and then you can click restore to go back to the four viewport layout. A faster way of toggling between one and four viewports is to simply double-click on the viewport title.
In the viewport meu, after the maximize/retore button, there are the viewport rendering options: wireframe, shaded, rendered, ghosted, x-ray, flat shade, and shade selected objects only. The useful ones to know are the first four. Wireframe will just show the outline of all of objects in the model. It is important to note that wireframe does not recofgnize overlaping elements, making wireframe very had to use in complex model. However, it is the fastest and lightest way of displaying a model. Therefore, with large complex files, it will allow you to move around the easiest. Shaded will shade all the surfaces the color of their corresponding layer. This is usually what I have it set to. Rendered will shade the surfaces according to the material applied to that object. Rendered will also give you a better understanding of how lighting will appear in the final render. Ghosted is very similar to shaded but all the surfaces are also slighly transparent, so you can see objects behind them. To demonstrate these viewport rendering optioned. I created four 2x2x2 boxes. I set the top view to shaded, the perspective view to ghosted, the front view to wireframe, and the right view to rendered. As you can see, with the first three the boxes are colored based on the layer they are on. If you look in the layer panel, all the layers have a white circle after the color option of the layer. This the the Rhino Render material. So, in rendered, all the boxes are white in appearance. Both the layer color and the render material can be changed by left-clicking on them.
Making Curves
The curves menu is, as you would expect, where you will find all the commands for lines and curves. For those with AutoCAD experience, the line, polyline, circle, arc, and offset commands are pretty much identical. Rectangle is also pretty intuitive, but there are some important options. The normal behavior of rectangle is corner to corner, a rectangle defined by only two points. 3 Points, which defines the rectangle by three points rather than just two, is a very useful option. With it, you first select the origin, then the width, and finally the length. Within the curves menu, the two remaining commands that I’m going to cover are extend and fillet. Both of these are again similar to AutoCAD, but I think it’ll be helpful to just go over them as they can save you a serious amount of work. When you select extend, Rhino will prompt you to first select to boundary object. After selecting a boundary object, you will be prompted to select the line to extend. In this example, the bottom line will be the boundary and the vertical line will be the one extend. While extend is a very intuitive command, fillet is not. Fillet is a very useful way of joining two lines. What distinguishes fillet from extending and triming lines is that you can auto trim lines, which just saves you some time. But, as you can see in the example below, you can add an arc to connect the two lines. The first fillet has an arc radious of .25 inches, the second has a radius of 2 inches, and the last one has a radius of 0. As you can see, a radius of 0 gives you the same result as extending the vertical line and then triming the horizonal one.
The last two commands in the curves menu are both under free-form. These are the splines that you will make to create curves. Splines are not the easiest thing to explain, but once you start using them, you will develop and intuitive understanding. There are two main types of splines. One is with interpolated points. In this case, the curve will go through the points you make and the control points are interpolated by the computer. In the other case, the points you make to define the curve are the control points and the curve is averaged between all the points. In the example above, the same points where selected in the two curves, but the top one interpolated the control points so that the curve would go through the selected points. The second used those points as the control points and averaged the curve between them.
Making Surfaces Under the surfaces menu, there are a lot of commands that are very important to creating complex geometry. Having come from Revit, you probably have done very little work with surfaces, as virtually all of Revit deals with solids or lines.
The first command under the menu, plane, should be fairly self explanitory. For the most part, it works just the same way as the rectangle command, except where the rectangle command just created a curve, the plane command creates a flat, planar surface there instead. The real difference, in term of functionality, with the rectangle command is that it doesn’t default to corner to corner. It is inteligent enough that if the your second point for
the plane is orthogonal to the first one, as a plane cannot have a width of zero, then you are obviously wanting to create a 3 point plane. The next command I’ll cover, as seen in the first example below, is planar surface. It’s an incredably simple tool. Let’s say you have a rectangle and you want to make a surface bound by that rectangle. You can select the rectangle and click on planar surface. If some cases, where you might want both a surface and its outline, this is a simple, but not the only, way of doing that. However, in the first case below with such a simple thing, and if the outline isn’t necessary, you can just use the plane command. Where planar surface is handy is when you have a complex geometry with cutouts and an irregular outline. This is where is can really help you save time. Once you start working with surfaces, you need to start learning about booleans and other similar functions. This often take time and can cause some frustration with more complex geometry. But, with planar surface, you can just model what you need with curves and polylines and the select everything and click on planar surface. This can be time saver. As you can see in the second example below,
Probably the most important command in the surfaces menu is loft. What loft does is that it takes a series of curves and defines those as profiles of a larger surface. While the setup can be a bit time consuming and learning to get the exact shape you want can take a bit of trial and error. This is the way you can create complex, organic-looking surfaces. In the example above, the lofted surface is black while the profiles for the loft are red. Lofts are very similar to blends in Revit, but as you build the loft, you have many options, as you can see below for controling exactly how you want Rhino to loft the profiles.
Coming from Revit, sweep and revolve should be very familiar commands to you. Rhino adds to sweeps by having one and two rail sweeps. A rail is the path a profile sweeps along. One rail sweeps function identically to sweeps in Revit. With a two rail sweep, one side of the profile sweep along one path while the other side of the profile will follow along a second path. In many ways, this command functions similarly, but not identically to the sweep blend command in Revit.
Making Polysurfaces The solids menu is the menu you will mostly spending your time. This is where Rhino really starts to stand out from AutoCAD and Revit. Considering the heavy investment you have had in Revit, there are some important things to notice in Rhino. Firstly, with Revit, Autodesk tried to simplify 3d modeling software into extrusions, blends, and sweeps.
Let’s start out with the basics. Boxes, like rectangles and planes before them had several ways of being created. The default behavior for box is to select the origin, then form a two point rectangle, and finally you select a height. You can also choose a 3 point plus height box where you create a 3 point rectangle and then select the height. For a sphere, the defualt behavior is to select the origin then select the radius. Cylinder and cones are very similar to spheres, but you also choose a height. Boxes will be the building blocks of many of your designs. They are great for massing as well as for walls, floors, or even 2x4’s.
Extrusions are nothing new to you, having come from Revit, but like sweeps, there are a lot of differences. Firstly, there are many types of extrusions. We’ll start with the straight extrusions. In the example above, we have a rectangle and a plane on the left. To take the rectangle and create the cube, I used extrude planar curve straight. However, if you already have a surface, you can use extrude surface straight to form the exact same cube. You will start to notice the differences between Rhino and Revit extrusions here, where you are prompted with several options: direction, both sides, cap, and delete input. Direction, as you would expect will select the direction of the extrusion. The only time you would want to choose that option is when you want to extrude a object in a direction different from its normal. Both sides is an option to extrude up and down or any two opposite directions at the same time. Cap is an option to cap the two ends of the extrusion. Except in certain conditions, I would suggest you always leave cap on. And delete input also makes a lot of sense, it will delete the source geometry. In the case above, it will delete the rectangle. Some
additional extrusion commands are extrude along a curve, which is very similar to sweep, and extrude surface to a boundary, which will extrude a surface until it reaches a boundary surface. Extruding to a boundary is very helpful if you want to the top and bottom surfaces to not be parallel to one another.
Booleans Now that you know how to build objects in Rhino, it is important to learn some basic ways of manipulating them. The most important set of commands when working with polysurfaces are booleans, which can be found in the solids menu. A good way of understanding what booleans are, is to see them as ways of adding and subtracting polysurfaces. Booleans can be quite finicky with complex polysurfaces and this is where best practices with model making is paramount.
Above is an example of a boolean union, the default behavior of the boolean command as well. In this case, the cube and sphere are on layers 1 and 2, respectively. I then performed the boolean union command, and the two polysurfaces became one polysurface with all overlapping surfaces removed. It is also important to note that the new polysurface is on the active layer and the two source polysurfaces no longer exist. While boolean union may seem just like the join command, it is not. I’ll discuss the proper use of join with polysurfaces later in this tutorial. Join polysurfaces will allow you to group multiple polysurface. However, each joined polysurface will remain a separate polysurface, in terms of geometry.
Above is an example of a boolean difference; where a boolean union added the two polysurfaces, a boolean difference subtracts one object from another. In this example, you can also see that the order you select the objects has an effect on the boolean, as you are subtracting object a from object b. Like the previous example, you have the two objects on their respective layers on the left side. In the middle, the sphere has been booleaned out of the cube. Thus, the sphere is intact and the ovelap between the cube and sphere has been removed from the cube. On the right, the order was switched and the cube was booleaned out of the sphere. This time, the overlap was removed from the sphere. You will also notice that both objects remain on their original layers. In the example below, you can see a boolean split. There are a few reason why you would want to use a boolean split. Sometimes, because of certain oddities in the geometries, a boolean difference will fail while a boolean split will not. For the most part a boolean split will act the same way as a boolean difference, except the overlap is not deleted. When you perform this command, you will be prompted to select the object to split, and then you will be prompted to select the cutting object. This make the command a bit more intuitive and easier to understand than boolean difference.
The final boolean command is boolean intersection. In the above example, like the previous ones, the two objects are represent on the left. Also like the two previous examples, the order in which you select the object has an affect on the resulting geometry. With a boolean intersection, the overlapping parts of the polysurfaces are the only things preserved and the rest of the polysurfaces are deleted. While the results may be the same in this example, the two remaining pieces are taken from different polysurface and in a more complex situation will be different.
Scaling The scale, or scale3D, command should be very familiar and intuitive. If you have used AutoCAD, scale works the exact same way. For those who have not used it, when you select the scale command, you will first be asked to select an object to be scale. Next, you will choose an origin point for the scaling. At this point, you can choose to either input the scale factor in the command line or select the first reference point. If you put a scale factor, the object will be scaled, and you are done. If you pick a first reference point, you will then be prompted to select the second reference point. The ratio of the length between the second reference point and the origin to the length between the first reference point and the origin will be the scale factor for the scaling.
What is really nice about scaling objects in Rhino as opposed to AutoCAD is the following two commands, scale1D and scale2D. The scale command in Rhino and AutoCAD scale all
dimensions equally. Above, you see an example of the scale command on a sphere with a radius of 1. On the left in the image below, you will see an example of scale1D on that same sphere with a radius of 1. It is only scaled along the y-axis. So the section along the xz-plane is stile a circle, but the sections through the yz-plane and the xy-plane are elipses. On the right is an example of scale2D on the same initial sphere. Now the sphere has been scaled in the x and y direction. So, the section through the xz-plane and the yz-plane are now elipses abd the section through the xy-plane is a circle.
Arrays In the next image, you will see an example of the array command, which works similarly to the array command in most other programs like AutoCAD and even Illustrator. While command isn’t anything new, there are some important things to note. Once you have selected the object you wish to array and select the array command, you will be prompted to select the number of objects in the x-direction, y-direction, and z-direction. You will then be prompted to specify the distance between the objects in each direction. While you will often not want to array an object in all three dimensions and it will seem annoying to have to still go through all the options for a three dimensional array, the control you have in arraying objects is very nice. Once you have selected all the options for the array, Rhino will preview the array for you. At this point you can either reselect any of the various array options and alter them or you can hit enter and the array will be made.
Expoding and Joining Exploding an object, using the explode command in the edit menu, can be very useful. What the explode command does is it takes a polyline or, in the case below, a polysurface and explodes it into its component pieces. In the case of exploding a polyline, you will get all the line segments that made up that polyline. With a polysurface, the explode command will result in all the surfaces that made up that polysurface. Please note that the original polyline and polysurfaces will not remain after exploding. Once you have exploded an object, each piece can be select independent from the rest. So, in the exampe below, I changed the layers of the faces on the middle cube. You can also delete or modify each face independently now. Now that you have an exploded polysurface, you can join it back together using the join command. Joining multiple lines will result in a polyline. Joining multiple surfaces will result in a polysurface. Below, I exploded the right-most cube and then joined the six resulting surfaces. Also notice that the joined surface will be made on the active layer. The join command should really only be used for joining lines into polylines and surfaces into polysurfaces. As mentioned above, you can join multiple polysurfaces so that they can be selected as a single object. However, they will not be a single polysurface, in terms of their geometry, which can become problematic later on. So, it is important to you use the appropriate command for what you intend to do.
Resources http://www.rhino3d.com/tutorials.htm http://vimeo.com/rhino http://www.pxleyes.com/tutorials/rhino/ext/ http://rhinotoday.com/category/tutorials/