Page 3 - In which we add details
and finish the Mag Wheel.
Step 48 -
The first detail we need to add is the hole through the rim that the valve
must pass (so we could inflate our virtual tire). Make a cone using
the Solid>Cone {Cone} command. Make it whatever size is appropriate
given your scale then position it poking through the rim midway between
two spokes.
Logic -
If small details that we unconsciously think should be there are missing
the object will not look quite right. These are often easy details
to add and well worth it if you want realism in your object. If you
want a low poly model for gaming or such, it would be wise to skip details
such as this and just add them in the texture map.
Step 49 -
Use the Solid>Difference {BooleanDifference} command to subtract the cone
from the rim. Select the rim first, enter, then select the cone and
enter. Fillet the top edge of the resulting hole using the Solid>Fillet
Edge {FilletEdge} command. Type in a fairl small radius (I used 0.4)
and click on the edge of the hole that faces the centre of the wheel.
If it doesn't work as expected try a different radius.
Step 50 -
The other detail that's missing is some sort of corporate logo. I'm
making up a generic design that has sweeping curves to fit the design of
the mag wheel. You can make whatever you want, but here's how I went
about mine. Start by drawing a new circle guide at world centre and
not extending past the edges of the central hub. Create a new layer
for the logo, make it active and turn off all the other layers (except
the Guides layer). I made a couple of more guides next. Select
the Curve>Polygon>Centre, Radius {Polygon} tool. Type 3 to set it
to drawing triangles. With Osnap Centre and Ortho on, draw 2 triangles,
one with points sitting on the circle guide and one entending past the
circle slightly and rotated 180 degree from the other.
Step 51 -
Now with Osnap Intersection on, draw a control point curve, snapping the
points to the intersections of the triangles and the triangle with points
on curve (as in the above image).
Step 52 -
Use the Solid>Pipe {Pipe} command to give form to the curve. Select
a radius (I used 0.15) that leaves some spaces between sections of the
curve and such that the surface does not extend past the circle guide.
Step 53 -
Select the circle guide and use Solid>Extrude Planar Curve {Extrude} and
extrude it some distance above the logo. The amount is not critical,
but must be some distance above the logo.
Step 54 -
Create another circle just slightly larger than the circle guide (use Osnap
Centre to align it). Extrude it using Solid>Extrude Planar Curve
{Extrude}, type "B" to extrude it both directions. In the front or
side viewport drag so that it is just a little thicker than the logo.
Step 55 -
Use the Solid>Difference {BooleanDifference} command, selecting the bottom
cylinder first, followed by the top cylinder. We now have a coaster
with a logo on it!
Step 56 -
We need to fillet the visible edges of the coaster. Use the Solid>Fillet
Edge {FilletEdge} command, setting the radius fairly small (I used 0.04
for mine). Select the top two edges of the rim and the bottom inside
edge. The bottom outside edge will be hidden so no need to fillet
it.
Logic -
There are very few really sharp corners on real objects. Filleting
them also allows for specular highlights in a rendered model that enhances
the realism.
Step 57 -
Select both the logo and the coaster, turn all the layers on, and turn
Ortho on. Move the coaster and logo up so that it is protruding from
the centre hub. Do a final cleanup by selecting all curves (Edit>Select>Curves)
and deleting them. The model is now finished and ready for export
to your rendering application.
I hope you've found this tutorial useful and relatively easy to follow. If you have any comments or questions feel free to e-mail me.
