Navmesh a long multi-part bridge

**Trick to Navmesh a Long multi-part Bridge**

(Without using 3dmodeling software)

by [TLB]stickman

Multi-part bridges normally won’t navmesh at all. This tutorial will explain a trick to move bridge
sections vertically (just a little bit) to have a “step” effect.

-We want to start with bridge head section . First things
first though. Make sure that it is Snapped to Ground. Zoom your camera
underneath the bridge head and make certain that the **terrain** underneath the bridge “ramp” does not touch the
bridge object. If it does, use the Level tool in the Terrain Editor to lower
the terrain.

**Hints:**

If you double-click the first bridge segment and write down
the Y/Pitch value, then subtract the Y/Pitch value of the bridge head, you will
see a difference of **2.11378**.
You can use this number if you want to build your bridges in place one piece at
a time instead of building the complete bridge first as we did in the first
part of this tutorial. Just snap your bridge\_head1 to ground, and then
double-click the bridge head. Then add 2.11378 to the Y/Pitch value shown and
use that value for **all** of your bridge
segments.  This will be your *starting position*.

The Stamp-Align buttons in the General tab of your editor do
not work properly for the wooden bridge. It aligns the wrong end of the bridge
heads to the bridge segments! It won’t align two segments either; it just stacks
them on top of each other at the same elevation.

If that much looks good, then we’ll continue. Double-click
the bridge segment closet to bridge head 1. In the Absolute
Transformation box that pops up, decrease the value in the Position –
Y/Pitch window by 0.01.  For example,
if the original value displayed was 30.85400, you will change it to 30.84400
for this segment. Now go to the next bridge segment and reduce it by 0.02
less than the previous segment. So using the previous example, this segment
will be changed to 30.82400 now. Do this for the remaining segments,
reducing the Y/Pitch value by 0.02 from the previous segment as before. Now
select bridge\_head2 and nudge it down a little (using the keyboard) so that it
is just a small step lower than the last segment. If the **terrain** under this bridge head touches the object, you will need to
lower the terrain as we did with the first bridge head.

I would recommend that you test your bridge’s navmesh prior
to navmeshing your entire map, particularly if you have a large map. You can
easily do this by creating a small Combat Area around your bridge, making sure
to select the “Used by Path Finding” box after closing the Combat Area. Then
run the navmesh program. It will only take a short while (a couple hours perhaps)
and can save you many hours later on when you are ready to run the final navmesh.
Make sure the Combat Area is on the Single Player layer of your level!

After you run the Navmesh program, open your level to verify that the bridge did navmesh properly. Be sure to select “Toggle Draw AI” from the Render Menu, and also “Toggle Draw Vehicle Navmesh”. If the Vehicle mesh is good, the Infantry mesh should also be good.

Although I did not actually run navmesh on this sample
bridge for this tutorial, I want to show you an example of a completed bridge navmesh.

From the looks of this, the navmesh did not make it to the
right-hand side of the bridge, but looks can be deceiving! If you turn off the “toggle
draw static meshes” from the Render Menu,

You’ll see that the navmesh did indeed go all the way
across. So be sure to turn off the static meshes when verifying that your
navmesh is good or bad. You wouldn’t want to run navmesh again would you? Well,
would you?

After your navmesh is finished, be sure to raise your bridge
segments back up to the original height before you run your lightmaps.

Good Luck!