Car Body - Adding Detail



We're getting close to the end of the body shaping. One of the major parts that we do have left however is the refinement of the hood and trunk. Turning our attention to the hood now, we are going to add some slope to it, and then separate it from the main car body. (We will discuss adding the appearance of thickness to the car panels later... this enhances the realism of the car, but will also enable you to "open" doors and hoods and trunks later, should the need arise.)



When we raised the center line of the top of the side panels to create the curvature our reference pics demanded, we created the need to modify the height of the cab edge.


The cab edge sits almost flush with the top of the side panel. Also the trunk and hood slope down and away from the elevated cab edge to the back and front ends of the car respectively.


We will correct the height of the cab edge and add the starting point for the slope of the hood by selecting all the points that make up the edge of the cab (around the front, sides and rear of the cab).


Make sure to select point pairs in places where our cab edge was defined with a double knife cut.

Then using the move tool, move them upwards on the Y axis until they are in place (top curvature of the door softens).

Now select the point pairs in the next double-row on our hood. This line defines the top of the hood, where it will separate from the car body.

Move these points upwards on the Y axis so that they come to a level just slightly below the points of the cab.


By gradually decreasing the points Y coordinates in successive rows from the cab edge to the front of the car, you can achieve a very natural slope. You may want to check point positioning in the side view (in wireframe view) to see how well the slope is being defined. It is sometimes difficult to eyeball the slope from a perspective view.



The second picture to the right shows further progression of this idea. All of the point rows, excluding the very front edge, have been carefully positioned along the Y axis to simulate the gradual slope of the hood.




The third picture to the right shows the positioning of the points that make up the bend in the hood, where the slope suddenly changes to being almost straight downward. The points were lowered considerably more as the slope makes the transition from gradual to drastic.

They were also drawn back a little on the Z axis to soften the curvature of the downward slope just a little.


Now a small adjustment may have to be made to the geometry defining the blend between the hood and the headlight swell.



The picture to the left shows two points that are culprits. These misplaced points lie on the line of what will be the edge of the hood. If a split were made now, we'd have a somewhat concave shape to this section of our hood.




By selecting these two points and moving them into a position that more closely matches the curvature of the hood, we have effectively corrected the geometry of the hood polygons, and have done little to disturb the shape of the headlight swell.


Now we come to the part where we separate the hood cage from the car body cage.

Select the polygons that will make up the hood. Make sure this includes the tight polygon row at the top of the hood. That row of narrow polygons is what will ensure the hood has a sharply defined corners when the split is made.





With these polygons selected run the Split command (found under the Structure menu, Edit Surface sub-menu...).

The polygons selected will become a separate object. I then placed this new object underneath a separate Symmetry and HyperNURBS parent objects.

All separate objects need their own HyperNURBS->Symmetry->Object hierarchy to work correctly.


Select the original car body from the object manager again. You will see that the polygons that were split off to make the new hood object are actually also still attached to the car body as well.

They should also have remained selected just as they were before the split command.

Making sure that you are in the structure manager in polygons mode, hit the delete key to delete the selected polygons from the car body object.




Whenever you delete polygons, remember you can clean up the extra points left lying around by switching to point mode, selecting all, and running Optimize with the Unused Points option checked.

Now you can see that two HyperNURBS objects are making up the car body and hood. There is also no visible deviation from one to the next. Don't believe me? Check the wireframe!!!

The hood separation worked great. Almost no visible transition between where the car body leaves off and the hood begins... It is pretty important to get the exact shape of the areas you want to split up finalized before splitting. Otherwise you will have to work at point manipulation and curvature matching between two objects, and that can be very tiresome.

When we add some panel thickness to our body parts, there will be more visual transition as to where the edge of the hood is, etc. It won't be uneven, but it will take away a bit of the unbelieveability we have now that results from having paper-thin surfaces.

Now we can do the same procedures to finish the trunk...