Join Dave Schultze for an in-depth discussion in this video Creating complex surface shapes using Network Surface, part of Rhino 4 Essential Training.
In this video, will cover what I've nicknamed Rhino's Killer Command. By that, I mean if you just met a caveman and could only tell him one thing about Rhino, you would want to show him the command called Surface from a Curve Network. So, yes, it's pretty amazing, but as you might have guessed, there are some requirements we'll have to cover. We will also the revisit those very handy commands, the Offset and Surface from planar curves that we've used previously. So, let's get started by looking at this set of a curves for a robot shoe.
Notice that I have built these off of the construction plane, which is up quite a bit higher. So, what I did was move the construction plane down to this level. Let me go ahead and turn on this one object. So, this is just a simple, flat plane that I've used to move the construction plane down and we access that by Set CPlane > To Object, and you can see the grid snaps. So, that's the way I recommend that you draw on a different level other than the construction plane; just move it down to wherever you need it to be.
I am going to turn that back off. Another tip is I've drawn a, what I call Construction Box, just to make things a little easier to work within and snap to as I am constructing these sets of curves. They are additionally helpful because this frame allows you to rough out the shape and then gives you corners and edges and surfaces that you can snap to. Now if we look at the set of curves I drew previously - we will go ahead and highlight those - you'll notice that they are going in two general directions. So, why is that? Well that's how the NURBS surface works.
You have Iso Curves that flow in two directions, so that is exactly why we are building curves flowing in two directions to build the surface. Now another requirement is that you have boundaries that are typically open, that would be these ones along the outside, but other profiles can be closed. We'll see examples of that in just a minute. Let's go ahead and start the command Surface > Curve Network. I am going to select these.
It looks like there is five. Now when this dialog pops up, that basically means that you have enough curves for a proper solution. We have some options here. Let me go ahead and accept the defaults. So, there is this surface from a network of curves, but I am going to try it one more time with one other option. I am just feeling like this is a little too complicated, possibly, so let's explore one other option.
I have got that selected. I am going to hit Delete. I am going to restart the command, select those five curves again, and now I'm going to switch to Loose. The A,B,C,D gives me conditions at several locations. I am going to switch from match to position exactly to keep it loose, which almost every case will make the resulting surface much cleaner and simpler. I am going to hit OK, and as you can tell right off the bat, its two or three times less Iso Curves on the surface.
So, that is a smoother, cleaner surface, which will greatly minimize any future problems. Now before we do any more work on this foot, I am going to show you another example with a similar set of curves that are almost completely closed. This is just a partial surface with an open bottom. Here is a set of curves I generated earlier. Let me see how they turn out. Surface > Curve Network. You can see when there is more curves you have less options to go with Position or Loose.
So, we will select OK to accept. So, it's a little bit more complicated than the first one, but it is one single surface, and it is as smooth as possible. We can verify that by turning on the Control Points icon on the menu bar. I am just going to pick a group of points, and you can continue to edit in that manner.
I'll turn the Control Points off. Close that layer. I am going to go back to the original foot. I am going to select the surface, do the Zoom Selected to make this a new center of the screen and the center of rotation. Now here is a great technique. A lot of times, I build a surface, and then I am going to start using its edges to then build additional surfaces so I don't have to build curves all the time for every single surface.
So, I am going to start by selecting this curve. I am going to have to jump to another Viewport. So, I am going to go to the Front and we'll take that curve and create an offset. I am going to offset a distance of just 1 to make it easy. I am going to switch back to the Perspective Viewport here and notice that the offset comes off 90 degrees from every point.
But that actually drops it down a little bit too low here. I want to have this have a flat detail on the ground. So, we can just do a quick trim and use this frame I constructed earlier - it's a cutting object - and then just select those little points that overlap to get rid of those. I am done with the frame. I am going to select it and the center line and just hide then temporarily to get them out of the way. Now, this first curve for the network surface and the offset are on the same plane.
So, you guessed it. We can make a surface from those planar curves. However, we have got an opening right here at the bottom. Let's go ahead and close that off with two straight lines. Now I think we are ready for the Surface > from Planar Curves, pick in the edge, Straight Curve, the offset and the opposite edge. Right-click when you are done, and now we've built a nice clean cap there.
I am going to go ahead and continue working on this to show a few more tricks. I am going to have this do a little recess. So, I am going to go to Surface > Extrude > Straight. I am going to select that curve. I want to go in 1, so I am just going to type it on the keyboard, Enter, and now I am ready to cap that off. So, as we did earlier on the front lip, I am just going to draw a straight line, corner to corner.
I have got my End Snap on, so I know that that's going to work. Go to Surface > Planar Curves, select that edge and that curve. The Robot shoe is capped and closed. Now I probably would finish this off by creating a bottom and then taking the leg and shoe and moving them to one side or the other and then mirroring them so it is equally symmetrical on the opposite side.
But we will skip that for now and wrap up. So, the Surface from curve network has many, many variations and endless possibilities. But these few examples should give you an idea of its potential. So, if organic modeling is your area of interest, it is well worth the time and effort to practice and seek out other tutorials on this method of modeling.
- Understanding 3D terminology
- Viewing a 3D model in Rhino 4.0
- Manipulating objects with commands
- Creating curves, surfaces, and solids
- Applying transformations to 3D objects
- Creating unique shapes with Boolean operators
- Snapping to objects and planes
- Defining curve and surface degree
- Prototyping a 3D model
Skill Level Beginner
Q: I'm noticing several differences between the options that author shows in the video and my copy of Rhino. For example, I can't select curves on the edge of a surface or turn on control point when vertically extruding a closed surface like an ellipse. Also, I do not get the Sweep option. I'm running on Mac OS X Snow Leopard.
A: This course was recorded on a Windows computer. As of February 2012, Rhino for Mac is still in beta, so it is not yet a full-fledged product. Wait until the full version comes out to see if these issues are resolved.