I Hope this helps you guys as it has helped me, I found this over at NG
An excellent way of getting ge data into btb.
In 3D Route Builder you can also smooth elevations in selectable gradiant steps and buy distance. Just brilliant for smoothing the incorrect height data from ge (no more 20 ft spikes in the track!).
I have edited this post to make it easier to follow.
Read it carefully
Next, you want, open Google Earth, choose your stage and save the track kml.
Now, go to
http://www.gpsvisualizer.com/elevation and in choose a file section, take your KMl stage file.
The next step is, choose the save format, (I choose GPX) and now click in Convert & Add Elelevation. save and rename file to (trackname.gpx)
It's done! Now you need Install (If you haven't got, 3D Route Builder and click in File - Open Route and there, choose your GPX file.
Now, you will see a elevation data with a altimeter line and lot of numbers colums and data under of it.
You need press Ctrl + A for select in blue all the colums and then go to Route - Altitude - Update from Geo Tool and now, the software start to update percent by percent the altitude of GPX file to get, better and "accurate" elevation data.
(added by me) Further down same menu goto smoothing and play with settings for 'point averaging'. you can zoom in close to track to check smoothing amount.
When it finish, click in File tollbar and choose the Export option and save it in GPX file and then, export again but in KML file!
Now, It easy, open Piddy's BTB and import the route like open ended and All samples imoprting options................
Should solve any problems you are having now with ge data.
plus takes so much work out of it!
I just did the Wilson's Promontory main rd in to the national park using this method and comparing to the other way (30+kms) it's a hell of a lot more acurate....