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Aaron, a request

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Aaron, a request

Postby MiToVo » Mon Jan 29, 2018 4:32 am

Hi Aaron,

I have a request for you, for something to implement into L3DT..

Can you please implement a warning, or something, that that informs the user that clicking a single checkbox could alter the look of their terrain to the point of being unrecognizable, in ways that are not at all expected or even understandable, and that it might not be reversible?

I just lost hours of work on a map project, because I clicked one checkbox during the generation process: "flood lakes".

I thought, naively, that clicking that box would simply do what the label describes... find depressions that could become filled as lakes, and fill them with water. I had no expectation, nor warning, that clicking that one simple, innocent looking checkbox would turn my entire map (4096x4096 - yes, my copy of L3DT is registered) into geographical swiss-cheese, with holes all over the place, all sense of form and shape that it had completely destroyed. It was unrecognizable from the map I'd been working on just moments earlier.

And worse, when I tried to undo it, something went wrong and the heightmap prior to that process was completely lost, unrecoverable, costing me hours of work. This is despite saving frequently. It seems every time you update the map, it overwrites the same images, instead of at least keeping a back-up copy saved that can be restored in case such issues as mine, or others, arise.

As great as L3DT is, I notice this happen a lot when using tools. It often seems like a single process is doing far more than its label describes. Adding the slightest bit of erosion - the lowest possible amount - utterly changes the entire terrain, lowering peaks and making the terrain, again, seem unrecognizable. I've not seen this happen with other programs. In other programs, if I say "add some erosion to this mountain area" - the mountain maintains its overall shape and height, and merely has the desired effect applied to make it look eroded. L3DT is the only program I know where adding erosion is tantamount to saying "Erase this land feature from existence, please".

Thanks for your time.
Last edited by MiToVo on Tue Jan 30, 2018 2:49 am, edited 1 time in total.
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Re: Aaron, a request

Postby MiToVo » Tue Jan 30, 2018 2:42 am

So just to follow up with a visual of what I mean by a single change causing vast, wide-spread changes that ruin the entire map...

Here's a current in-progress shot of the work I'm (re)-doing for my project... It's a backup copy, so I don't risk permanently losing all the work again.
Before

Now, to test something out, I made a single change.. I edited the design map and added a single mountain. That's it. I didn't add any kind of other filters to it. No other checkboxes were ticked. I didn't apply it to the whole map. I clicked once on the design map with the special features > mountain > Large option, and that's it. After running the calculations again, I get this...
After


Now.. I'm not a geologist, and I won't pretend to understand the complex calculations going on behind the scenes in L3DT, but I'm pretty sure *that* shouldn't be happening due to adding a single, not terribly tall mountain. It barely looks like the same landmass.

Is that expected behavior, or is something awry somewhere in the calculations being run? I can't believe such drastic effects are intended.
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Re: Aaron, a request

Postby Aaron » Wed Jan 31, 2018 12:28 pm

Hi MiToVo,

I apologise for these problems, which seem to be many and varied.

I'm running some tests now to see if I can reproduce the problem with drastic heightmap changes when flooding lakes is checked. In principle, this should cause some changes to the heightmap, because any time you click 'Heightfield->Generate map' (or use equivalent wizard option), the heightfield is wiped and generated anew from the design map, using a different random seed. General features should remain the same, but details may change. However, the changes observed seem greater than expected.

And worse, when I tried to undo it, something went wrong and the heightmap prior to that process was completely lost, unrecoverable, costing me hours of work. This is despite saving frequently. It seems every time you update the map, it overwrites the same images, instead of at least keeping a back-up copy saved that can be restored in case such issues as mine, or others, arise.


Ah, unexpected feature here. When you hit 'save', L3DT commits any unsaved changes to disk, and clears it's undo stack. In essence, you can't 'undo' anything from before the last save. This is clearly not what you expected, but it was done to prevent L3DT from filling unsuspecting user's drives with the undo cache. L3DT maps can get quite large, and the undo stack can be tens or hundreds (or more) times larger still, depending on what edits you do and how long your session is. I'll look at adding an option to preserve the undo stack, at least until the user does a 'save as...'. Hmm...perhaps I could ask the user if they want to clear the undo points after a 'Save' operation, with a 'don't ask me again' checkbox. Perhaps I should also add an option to save a full project revision point (lasts for life of session, or until map is closed). I'll have a bit more of a thinker about this...

I'll have a look into the erosion problems at my earliest opportunity.

Thanks for taking the time to detail these problems; I really appreciate the feedback, and I'll do my best to sort out these issues. I'm sorry my bugs and/or design choices have caused such frustration and lost time.

Best regards,
Aaron.
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