I have been working on a landmass, that is 4 grids large. Upon reloading the game and going into the height map viewer, I always get a square at 0,0. I smooth it out, I flatten it, I make it look like it's supposed to in that region, but everytime I reload, it drops the floor down, well below sea level. I also get various alerts when saving about terrain data, I have gone over every square in the grid and using the terrain edit tool, I smooth out and flatten anything that looks odd.

I would like to get underway laying out the regions and cluttering it and get it ready to add my cities and such, but I don't want to put in that much work to have to find out it's having issues right from the beginning.

Am I missing something? Is the overall sea floor too low?

In case any one wonders, these are height maps generated by a combination of Fractal world Explorer and Photoshop.

Here's a pic of what I'm looking at: http://img8.imageshack.us/img8/1135/heightmap.png

I'm also constantly faced with this annoying issue. I do not use Fractal World Explorer or even Photoshop, but that shouldn't really make a difference as I can't seem to get rid of the problem. Just like you I've tried to smooth it out using landscape editing, but every time I save, the editor reports it cannot save land height data for the cells in which this problem occurs.

Does anyone here know what to do?

Okay, so now I am getting somewhere, but no questions answered. I go through and smooth out all the tears and 'issues'

I save, and get no errors.

I close the CS and reopen it.

I choose my main esm, and my plugin. Set plug in active.

Add a lamp post somewhere. Anywhere.

Save, no errors.

Close CS

Reopen CS. Remove placed lamp post. Save. No errors.

Close CS. Reopen CS and load esm and esp.

Change a small piece of a land at -12, -14. Save. Errors start popping up.

After I do all the above, it keeps repeating whenever I do any landscaping. It would seem that my editing is causing the issue? That does not make any sense. I tried it with another heightmap and am getting the same issue. There has to be something I am missing...

When you save a heightmap in the heightmap editor, it will create an error in the bottom corner of each quad (32x32 cells). For most landmasses, only (0,0) is affected, but for larger landmasses with multiple quads, there will be errors every 32 cells (0,31), (0,63), (31,0), etc. These are the cells you will receive error warnings about. This happens every time you save a heightmap in the heightmap editor.

You have to fix these errors in the render window using the landscape editor (H). If you then go back and alter the heightmap in the heightmap edtior, you will get the same error again. This is a known bug. More info is available at the CS wiki in the http://cs.elderscrolls.com/constwiki/index.php/Heightmap_Editing#Notes.

Although annoying, these errors only take a few seconds to fix. Best practice is to work on your heightmap -> save heightmap -> go to cells in the render window and smooth out error -> save mod -> work on heightmap -> repeat. Once you're satisfied with your heightmap and are finished making changes to it, correct the errors one last time in the render window and make it look pretty. If you have to edit your heightmap in the editor again, you'll have to fix it again, so don't worry about making it perfect each time you fix it, only when you're done with the heightmap. It always seems like a big chore when you first start using the editor, but it is literally about as difficult as sharpening a pencil. There is nothing wrong with your heightmap, but you will experience missing land mesh in-game if you load your mod without fixing the error. Fix it up, and your land reappears.

Yeah. It is as difficult as sharpening a pencil. Once upon a time ago, I remembered something like this. Anyway, the frustrating part was when something would change, sporadic tears throughout the map would happen, even some vertices shooting up into the air. If I had some screen shots, I could show you, but it looked like giant columns rising into the air int he distance. And happening less frequently than every 32 cells. MUCH LESS!

Anyway, I think I got it under control, your explanation has helped me more and I think I'm good to continue Thanks a bunch guys!

You might want to check the Construction Set Wiki. It has an article about landscaping and heightmap editing that describes the above mentioned problems, if the replies here have not already solved your problems.

I see a heightmap, but I do not know if you are actually adding regions and the land textures. This is important as well. If you are generating and overlapping regions, they can lead to rips in the heightmap. You must consider before generating regions and texturing of repairing your entire heightmap at once and rechecking over, and over. There is also a tool called 'Land Magic' that claims to fix your rips in one clean sweep and though I've used it for a land mass at 8.5 times the size of Cyrodiil, I'm not entirely confident that it did the trick. Though, I have yet to make a clean sweep of the entire map. Care must be taken in using it as it's documents states, but if you are at the point prior to creating landscape textures. Give it a try, you can find it at TESNexus. Still the same, I highly recommend constant checks for rips at later dates and especially during landscape generation.

Here's a link with a few tutorials and visuals to assist you.

http://merp.straygenius.com/forum/viewtopic.php?f=115&t=8388