Car Body - Adding Detail

Panel Thickness - Hood, Trunk & Door


Now that we are finished with the arduous task of adding thickness to the edge of our large body sections, we can see the end of the main body work in sight. In this step, we will add the final thickness to the hood, trunk & door panels. We will be using a different method than previously though... just to make things interesting!



(For clarity, other objects are hidden at this time.)

Select all polygons that make up the surface of the hood. Make sure they are all aligned and facing outwards from the car.


Using the structure manager in polygon mode, you can see all selected polygons are highlighted. Use the Edit menu Copy and Paste commands in the structure manager to duplicate these polygons.

The surface of the hood will look very faceted, perhaps since there are two sets of polygons in the exact same places... not to worry!


The polygons that were just pasted should be the only ones highlighted in the structure manager. That is ideal...

In the Structure Menu, use the reverse normal command. The pasted group of polygons will flip direction. Again, don't be alarmed by any ugly display of these polygons, especially if you have backface culling enabled.


With the flipped polygons still selected, use the extrude tool to extrude three times in very small amounts each time. The target thickness for the total of the three extrusions is the same thickness as we've made all the rest of our car body. The reason for three extrusions instead of only one is to ensure nice sharp edges.


Now most of the display problems, and faceting of polygons should have been resolved when the extrusions took place, and the polygons no longer occupied the same space as each other.

Selecting all polygons shows there is still a problem to be dealt with in the center.


A close up of the wireframe reveals what the problem is. When extrusions are done, edge polygons appear around all sides of the polygon being extruded. This includes objects that are being used in a symmetry object. The polygons appearing on the plane of symmetry are essentially 'doubled up' as they are being mirrored as well.


These polygons are completely unnecessary. Select all of the middle 'edge' polygons along the centerline of the hood an delete them.

Optimize to eliminate unused points.



You can see the result is a nice smooth hood with good sharp edges and a decent looking thickness to it.



The technique for the door is the same, with one advantage: we won't have to worry about deleting any polygons appearing on the plane of symmetry!

Select all polygons (make sure they are all aligned and facing outwards!!!)


In the structure manager, in polygon mode, copy and paste the polygons. Once again, the faceting appears, but we just shrug it off!

The pasted polygons remain selected.



Use the Structure menu to reverse the normal direction of the pasted polygons. (The reverse normal command also appears in the popup menu).


Use the extrude too to create three very thin extrusions. Once again, the target thickness for the sum of all three extrusions is the same as the consistent thickness we've been trying to achieve with every other panel.


The door panel should be complete now.

Here's a look at how it turned out.


Finally, we do the same technique to the trunk, and then we can relax about panel thickness and get on to the better stuff!

The trunk will be the same as the hood.

Select all polygons, and make sure the normals are all aligned and facing outwards.



Using the structure manager in polygon mode, copy and paste the selected polygons.



Run the reverse normal command...



Perform three extrusions until the trunk thickness is consistent with the thickness of our other panels.



Select the middle 'edge' polygons that lie on the plane of symmetry and exist in the middle of our trunk.



Delete the offending polygons, and watch as the trunk surface becomes smooth and continuous across the line of symmetry.

Mission accomplished!

Panel Thickness - In conclusion

Well, we just spent a grueling amount of time adding what seemed to be a rather irrelevant detail to our car model. But then, grueling amounts of time is what 3d is all about isn't it? :-)

Whether or not this part was fun or not, it certainly DID help the look of the model, as a render shows... Now the paper thin appearance of the panel surfaces is gone, and the thickness, while not photorealistic by any stretch, lends a lot of believability to the overall look.

Now it's time to move on to other areas!