Car Trim
Trim - Rear Bumper
The rear bumper is half done already and we really didn't have to put that much effort into it since it was just a copy of the one we were working on for the front. That is just one of those lucky little byproducts of having objects in your scene that share similarities. Learn to recognize where the similarities are and you learn to recognize what you can recycle and model with minimal effort (but maximum effect!).
Now we return to where we left the rear bumper last, when it was just a copy of the front bumper at half completed stage. You can see from the picture that it already works pretty well... it just needs a bit of modification, and then we can go straight into making it unique.
Here I selected all three rows of points of the internal 'corner' of the bumper where the bulge begins. In the front of the car, the bulge was formed around a much larger swell in the original car body, but in the rear of the car, this swell is much smaller. Once these corner points are selected, you can move them out along the X axis so that the bulge becomes narrower and conforms more to the shape of the rear car body.
The next thing to do is build a pocket (or carriage) on the rear bumper on which to seat a spare tire object.
For that reason, I'm getting rid of the middle two rows of polygons. Make sure to select all polygons around the entire surface of the bumper in these two rows... (i.e., don't restrict selection to visible when choosing these polygons, or you'll be making extra passes to pick up the back surfaces).
Once the polygons are deleted, the end of the bumper facing the middle of the car should be open, making the bumper seem paper thin and tubelike. This is NOT what we want, so I have created polygons on the end with the bridge tool to form a finished surface..
I was lucky that the point layout of the end of the bumper lent itself well to using only quads to patch it up... (or maybe I planned it?...) ;-)
A view from above shows the state the bumper is in. See how the HyperNURBS action has rounded off the end surface of the inner bumper end? We want something a little less organic, and also I want to be able to extrude some geometry from near the bumper end to form that carriage I was talking about. I'll need some smaller polygons to work with...
...so using the knife tool to cut near the end of the bumper comes in handy twofold. First, it sharpened the geometry on the bumper end a bit due to the higher mesh density, and secondly I now have some reasonably useful polygons to use for extruding purposes.
Speaking of those useful polygons for extruding purposes... select the resultant two polygons on the outer surface of the bumper that appear at the top and bottom of the object. Use the extrude tool to extrude them outwards (they should create a forked object like this). Remember to just make a little extrusion at first followed by a larger one... the small extrusion keeps corners and edges sharper...
Observe from the side view to gauge about how far you need to bring the carriage bars out from the bumper. Remember we are going to try to fit a spare tire in there, so we'll want at least a tire's thickness, plus a little more to seat the spare on a bit of a slope...
Select all polygons of the prongs and make a knifecut near the end of each prong. You want the knifecut to be about as far from the end of the prong as the prong is wide...
...that way, we can select the polygons formed on the inside ends of each prong and extrude them towards the plane of symmetry.
You can get the ends close for now, but then switch to point mode...
... and use the Set Value command to set the points to an X value of zero. The points will then meet perfectly on the plane of symmetry. The carriage closes up and the bumper is once more continuous from one side of the car to the other.
Which is all well and good, but the long narrow bars don't look too sturdy! We need to model some braces.
From the top view, select all the polygons on the back of the carriage, and make two knifecuts about halfway between the middle of the bumper and the corner of the carriage portion of the bumper.
These knifecuts should be about as wide apart as the size of the carriage bars.
Select the two polygons on the carriage bars facing each other as shown.
Now we can use the bridge tool for something other than creating polygons from points...
With both polygons selected, when you run the bridge tool the program basically deletes the two polygons and draws the polygons that would 'bridge' the two areas together.
The result in this case is a post or brace is created between the two carriage bars.
Now on to some more of the little trim elements... hey, it's a 50's Chev, it needs some more chrome!!! (we'll skip the checkerboards though...) ;-)
The post is a good start as is, but looks a little organic when first created... to sharpen the edges, I selected all polygons of the post portion and used the knife tool from the side view to make two knifecuts near the very top and bottom of the post polygons.
The narrow polygons that are created by doing this tighten up control over the HyperNURBS rounding here.
I also wanted the brace to be recessed a little from the edge of the bumper tire carriage bars (just to suit my taste really...).
I selected the front and back polygon of the post and moved them inwards from the edge of the horizontal bars (not I didn't touch the narrow polygons to move them inward... the only reason they are affected is because they share an edge each with the polygons I am moving here!)
And in the gourad shaded editor view (above), it really doesn't look all that good...
But a render doesn't look too bad, at least in my opinion!