Why does Some of my Hightmap Flood yet Other Parts not?

[quarkphotonect]

Hi
I have a Big problem. I have Used Photoshop and Wilbur To create a hightmap for a Large island I am Imagining.
I import it into Terragen 2 and When i flood it with water Some parts Flood but a Massive bit in the corner Up the top does not flood. This area Is supposed to be under the sea. when i Flood that area it destroys some of my lo Lying terraain down in the other corner!! help! i have attached an image of my problem.
[attachimg=#]

[airflamesred]

Whats your water shader plugged into? How big is your heightfield because it won't conform to the curvature of the planet.

[quarkphotonect]

the Hightfield was big I would like it to be about 600Km long, my water shader was plugged into a lake but the lake was not plugged into anything else.
I really want to Make this hightfield work It is like my first terragen 2 goal to make the whole island work.

[Hetzen]

The lake object is actually a flat disc, so if you imagine a flat disc on a ball, the edges of that disc will be raised off the ball. This is what's happening in your scene, your 600km heightfield is covering more of the planet, therefore the curvature is falling bellow the edges of the lake object. Also, the radius of your lake object is not large enough to cover your 600km heightfield.

Another way of doing this, would be to copy and paste your planet object, and just connect a displacment shader with a constant scaler of 100 (this will displace the new planet to your water level) through a water shader into your new planet. So you have two planets ontop of each over, one being the land, the other the water.

[quarkphotonect]

Ok Thanks!
But I have another problem, My Heightfield is also flat it does not curve with the surface of the planet
also i am a Terragen Noob and mostly use the Tabs and very rarely use the node network. i only started to over the last weekend.
so i am not familiar with the more advanced functions. sorry heheheh!
But I am Appreciating all the help the members of this forum give me!! thanks! i hope i can fix this !!

[Hetzen]

Your heightfield should curve if you uncheck "flatten surface first" in the displacment tab in the Heightfield Shader

Here's a node clip file. Use "Insert Clip File" in the File menu. This will insert a new water group into your scene. I've labelled it up to make it clear what's doing what. The "Proxy Water" is just a solid blue colour, I use this whilst setting up a scene, then swap it for the "Water shader" when doing a render.