Model A: Creating the Grille

One of the little secrets about creating complex shapes in SolidWorks is that they aren’t all as complicated as they look. The grille is one example of this. Once you know what you’re doing, something like this is actually very easy to create.

First, we have to select a feature type to use. This is going to have to have curves in both directions, so it could be a boundary. The profile needs to change, and doing guide curves to change the profile would be too difficult. So it will be either a loft or boundary. In this case it really doesn’t matter, so I selected boundary, just because it’s the future direction of development, and clinging to the past is oh, so gauche (he says as he models an antique car).

The first thing I’d do to model the grille is realize that the thing is symmetrical, and that there is a sharp edge at the plane of symmetry. This makes things much easier.

Of course something else you want to do is to get a picture of one you like and work from that. Realize that this is a cartoon Model A, so I’m not really trying to recreate this 100%. It’s gonna be a little exaggerated in some ways. This image of the 34 coupe captures the flowing shape between the front fenders and the grille together. This grille is taller and more narrow than what I’m looking to create, but it has the overall form that I want.

You can start to model this part in one of two ways: draw the curve that becomes the “direction 2″ 3D curve or path for the boundary, or draw the 2D sections for “direction 1″. Direction 1 and 2 are completely arbitrary in real application, but I’m pretty entrenched with the old way of doing things, so I think of Dir1 as “loft/sweep profiles” and Dir2 as “paths/guide curves”. It doesn’t matter how you use the two directions, which is part of the point of the boundary feature to begin with – both directions are treated equally.

Ok, so I select to make the 3d curve path first. The 3d curve is essentially a C shape, angled back and curved in both directions. You can do 3d curves in a couple of ways, but the most important are the 3d spline, and the projected curve. In this example, I’ll use the projected curve. A commenter suggested having a look at 3D sketches, and I will get to that in my next post on this Model A where I look at creating the exhaust pipes and the sparkplug wires.

Projected curves tend to be confusing for people. Not sure why. Some people get it immediately, and some just don’t. Anyway, there are 2 ways to “project” the projected curve. The curve can be projected onto model faces, or onto another sketch. Projecting one sketch onto another is where most people who are going to get lost usually get lost. The sketches that you project are usually on planes that are perpendicular to one another. Sometimes you have options to pick different combinations of planes, such as front and top or front and side. In this case, front and top will be the easiest. Sketch onto Sketch projected curves essentially extrude both sketches through space, and where they intersect, it creates a curve. You can think of this like extruding one sketch as a surface and making a sketch onto face projection with the other sketch. You could also think of the projected curve function as being like a reverse drawing. A drawing takes a 3D something and creates 2D views of it. Projected curve takes 2D views and creates a 3D shape.

Actually, the grille in the image of the 34 coupe is slightly angled back in addition to being angled to the side, but I didn’t model it this way. I just took the easy route, but I’ll also explain the more complex operation as well.

So here are the two sketches. The arc with the dimensions was sketched on the top plane, and the spline was sketched on the front. Notice that the spline has 2 endpoints and a midpoint. The shape is controlled by the handles.

When you make a projected sketch from these, the grille will be essentially straight up and down because the arc is placed on the top plane. To get the grille to angle

the way it is on the image of the 34 coupe, you would need to put the arc on a slightly angled plane. Anyway, this results in a 3D curve.

3D curves are not as flexible as 3D sketch splines, but they are far easier to control. There is a lot of overlap between curves and 3d sketches, and a future post on 3D sketches will talk about a lot of this. SolidWorks has not put much development into curve features in the last many releases (variable pitch helix was I think the last change of significance). But they have poured massive development into 3D sketches in general. Even the new Equation driven Curve is actually a sketch element. I keep wishing they could dig themselves out of the terminology quagmire they’re in but it just gets deeper and deeper with each new feature.

Anyway. So with a 3D curve in place, now it is time to draw the sections. On the side plane, I drew the section of the grille at the top, and then in the same sketch I drew the section of the grille at the bottom. You couldn’t get away with this in days gone by in SW, but you can now. I still don’t think it’s a great idea, but this was just a model to create an image. Too many things can go wrong when you combine sketches with separate functions into a single sketch.

This image shows the top and bottom in a closed sketch, and an intermediate profile in an open sketch referencing the curve created earlier.

When making models for renders, remember that sharp edges don’t render well. Usually you want to have a small fillet on a sharp edge. In reality most edges that we characterize as dead sharp actually have a visible round.

The next step is to create the boundary feature. Remember that boundary uses some of the same rules as loft. The one I’m thinking of here is that if you want a loft to not twist, select the profiles from the ends that you want to connect. Same applies here. It is nice that with the boundary, you can RMB on a profile in the propertymanager and select Flip Connectors.

In this case we don’t need any end conditions unless you want to add some shape around the plane of symmetry.

In the end, the result looks like this. Remember to apply a shiny appearance. Just doesn’t look the same without it.

The next part to worry about is the mesh inside the grille. No, I’m not going to actually model it. This is a “looks like” model, not a production model, so shortcuts like this are permissible.

The easy way to do this is to make a surface of the shape desired and then apply a texture, ahem, I mean an appearance to make it look like slats.

This surface is easier to create than you might think. On the side plane, I drew an arc with a suitable radius to add some curvature to the grille. The arc went between the open corners of the boundary feature on the side plane. Then I used a Fill feature to fill between the sketch and the inside edge of the boundary. And that’s it. It will look better if you turn off  ”optimize”.

Finally, add an appearance. The vertical slats probably look better than the horizontal ones.

Big headlights, baby. Don’t be shy. Mirror and you’re done.

By the way, if you are impatient with how little information is here on this surfacing stuff, just go and buy the Surfacing Bible. I’ve re-read it recently, and, well, I’m biased, but I think it’s a really nice book.