Lakes in Fractal Terrain
pwiecek
Newcomer
Is all the water in Fractal Terrains the same level? Can I have higher altitude lakes or dry areas below sea level?
pwiecek
Newcomer
Is all the water in Fractal Terrains the same level? Can I have higher altitude lakes or dry areas below sea level?
Comments
Look in Maps menu at the top, World Settings, then click on Primary. You will see settings for highest peak and lowest depth.
The water level in FT3+ is world-wide. High altitude lakes or below sea-level land is not something FT does, sorry.EDIT: This was wrong, see jslayton's answer below.
Thanks
My version has a Tools>>Paint Values>>Water Level option that lets me paint into the water layer and Tools>>Actions>>Fill Basins as Lakes that will fill up low areas as lakes. Then there's Tools>>Rivers that will find rivers over the terrain.
My apologies, I am really too unfamiliar with the newer versions of FT3! I didn't even remember you could paint different water levels at different locations into the map now!
Does Fill Basin basically do the same thing (just automatically), i.e. painting in a higher water level in the basin area?
My answer probably sounded a bit snippier than it should have, sorry. I was outside pruning back a tree in the cool of the morning and lightly pruned one of my fingertips. It's fine, but it does sting a bit when I type.
The Fill Basins commands find areas that would be little dips in the terrain and figures out how deep the fill would be to make them flat-ish. If it's fill basins in offset, it find a very lightly sloping fill and will put that amount into the offset channel to fill up the little dip with altitude that forms part of a connected river network. Fill basins as lakes finds perfectly flat fills and will put the altitude of that filled are into the water channel, where they appear as lakes. Unfortunately, running fill basins as lakes will on a fresh world will get little lakes everywhere, at all scales. Running Fill Basins in Offset followed by Fill Basins as Lakes won't get any lakes at all because the places that lakes could have been would already have been filled by terrain. There are a few tools that would be helpful here (like removing all lakes smaller than some threshold), but nobody has written those tools yet.
FT's water channel does have some unfortunate "features", such as being able to paint in mountains of water in the middle of the ocean (and giant dry pits next to them, if desired). However, one of my goals was to give the user some very simple starting point and let them paint in things like rainfall and temperature (and water and some other things later on) to their heart's content. Things get slowly better (FT 1.0, for example, didn't even have selections) and I hope that sort of thing will continue over time. Vector scribbles, text, and symbols are on the wish list for FT4, but I can't even begin to guess when that might happen.
Once again, thanks.
Bu you can limit "Fill Basin with Lakes" by selecting an area first, right? That seems to work for me if I don't want to do it across the whole map.
Yes, you should be able to limit the effect where lakes (and general basin fill) are applied by using a selection. It's a mask-on-write operation, though, meaning that the fill structures are calculated over the whole world and then water is applied only to the masked areas. That kind of post-operation masking give results that are globally plausible, but may not be locally reasonable (for example, a selection that passes through the middle of a large basin will get a lake with a "cliff" along the edge of the selection; feathering the selection will get slopes in the water along the edges of the selections).
It would still be ok if you carefully drew the selection around the watershed for your area, wouldn't it - the ridge defining the catchment area?
FT will do physically plausible things if you force it to do physically plausible things, yes. However, it doesn't have much (if any) guardrails against physically implausible things and those are really easy to do. In this case, putting a selection around only a catchment area (which can be hard to do given the nature of the underlying surfaces) will fill in all basins in world, then only keep those filled areas that fall within the catchment area (the selection).
In a way, the existing behavior is good for experienced folks because they will get good results. It's bad for inexperienced users, though, because they put trust in the algorithms to do the right things and can be disappointed when others point out the implausibilities. However, that is true of all drawing tools.
Well, if nothing else works, I'll just do the lakes in CC3 after export & do without the dry depressions.
You can fill all the basins, then either eliminate those in FT3, or in the CC3+ export. That is what I have done.