Jumping over (or through?) difficult/impassable terrain

[Quixus]

How do you measure the distance if a jump unit wants to traverse difficult or impassable terrain like a wall or a forest? Do you have to actually go up on one side of the terrain and down the other side or is the horizontal distance enough?

 

Example: Could a jump unit move over a 4" high wall that is 6" away from the unit and still move 6" afterwards, or do you have to employ trigonometry to calculate the maximum distance allowed after traversing the wall (~2.6" away from the wall), assuming a wall of negligible thickness.

[ShinyRhino]

Jump and jet pack units ignore all intervening terrain, so you'd simply measure horizontally. Of course, that assumes you're landing at the same elevation as you started from.

If you land at a higher or lower elevation than you started at, you have to measure at an angle. So if you start 4" up into a ruin, and land at ground level, you're not going to be able to go a full 12" forward measured as the crow flies. You have to use that good old Pythagorean Theorem (or just angle your tape measure)!

[Quixus]

Are there any rules that support this varying treatment depending on your starting and ending elevation?

[ShinyRhino]

From the Movement Phase section:

 

"Models move up to 6" in the Movement phase. This represents most creatures moving at a reasonable pace but stopping several times to scan the surrounding landscape for

enemies, communicate with their commanders, identify the best lines of advance and so on. It is perfectly fine to measure a unit’s move in one direction, and then change your mind

and decide to move it somewhere else (even the opposite way entirely!) or decide not to move it at all. As you move the models in a unit, they can be turned to face in any

direction, but if a model does move, no part of its base can finish the move more than 6" away from where it started the Movement phase."

 

The above bolded section tells us that as part of movement, no model can ever move beyond its normal movement distance. For most models, that's 6". So the leading edge of the base can't exceed 6" from the point at which that leading edge started the phase. There's even a little diagram above this in the rulebook that illustrates how to move a model.

 

From the rules for Jump Infantry, we get the Skyborne section:

 

"When using its jump pack (whether moving, charging or Falling Back, as we’ll discuss in a moment) a model can move over all other models and all terrain freely. However, if the

model begins or ends its move in difficult terrain, it must take a Dangerous Terrain test."

 

By my reading of that, jump units move over terrain freely, meaning they don't have to measure vertically and then horizontally to change elevations like non-Jump, Jet, or Jetbike models. They just measure base edge to base edge. I've never seen it played otherwise.