Time to generate very large terrains?

[Kilo]

Hi folks -

First of all, I wanted to add my praise to Aaron for a fabulous program. Very, very well done. It's become my Atlas2 terrain machine!

I'm curious how long it takes to create very large terrains. I created a design map for the largest possible setting, so this sucker is huge. I'm pretty pleased with how the design map turned out. I'm now in the "channeling erosion" phases of heightmap generation, and each of the 50 phases is taking a little less than 24 hours to complete. Is that normal? I have a 2 GHz, 2 GB RAM machine. At current speed, it'll take about two months to finish creating the terrain, which I'm okay with (I don't need it any time soon), but if there's a better way without sacrificing the quality of the results, I'd be curious to know about it. My real fear is that we'll have a power failure or something and the computer will reboot before the heightmap is finished!

It looks like there is a lot more of the program to explore (I'm using defaults textures and climates at the moment), so I'll be looking forward to playing around with that (on our other computer, of course!)

Thanks in advance for any thoughts,
Kilo

[Aaron]

Hi Kilo,

The last time I clocked the generation time for L3DT, I got a figure of ~1 minute per megapixel on large mosaic heightfields using an AMD XP2600 (~2.1 GHz). As your heightfield is 16k megapixels, that works out as about 11 days. Of course, I have since tinkered with the terrain algorithm since I did those benchmarks, and it may be either faster or slower now, but not hugely so. The times for making the rest of the maps (textures,light maps, etc) are generally 50% or less than for making the heightfield, with the possible exception of the water table, which can be somewhat slower. The old benchmarks live over here, by the way.

Cheers,
Aaron.

[Kilo]

Sigh...

Well you knew it had to happen. I got up this morning to find that my computer had reset overnight. I'm back to the beginning of generating the heightfield. Ten days of work gone, ah well. But it was running significantly slower than you predicted so maybe there was something wrong with the last run. Here's a suggestion though, you might add in a feature that would cause L3DT to save its progress after each phase of erosion channeling (and every other phase, for the matter). When maps take weeks to generate, you need to be able to recover from a failure.

Just a thought!
Kilo

EDIT: Just figured out what happened to cause the restart -- I had the bloody Windows Automatic Updates turned on. I swear I turned that off...

[Aaron]

Hi Kilo,

Ouch, what a bummer. Regarding a restore function, I'll look into it once I've finished the 'undo' feature for v2.5a (very similar in concept).

Cheers,
Aaron.

[demi]

Hi Kilo,

What size map are you doing? 4 giga-pixel took just under 4 days to do the HF.


Hi Aaron,

This is a little embarassing but I will share it. I started a 2 giga pixel map a few weeks ago. I was doing some rather difficult stuff at work so I was tired when I came home. The map was on the making cliffs function and as usual I turned off the monitor before going to bed. The next thing I see is "Windows is shutting down". /sigh Seems I pushed the power button on the computer instead of the monitor. It would have been nice to be able to recover. I started over on 3/25 and completed now.

[Kilo]

Hi Demi -

It's 16 gigapixels, so it's gonna take a while!

Kilo

[demi]

That will take awhile.

Good luck on it let us know how long it takes.

[fusi]

i second the request to have l3dt store progress after each step/pass! that would be rather useful!

[Kilo]

Well, I've basically given up until the "save-as-you-go" feature is implemented. It's not the software's fault, but it's basically impossible to make the largest terrains as-is. In the space of 2-3 months' time you can just about be sure that something is going to happen that is going to make you have to start over and lose everything you've done so far. I had L3DT running on a separate machine. This is the fourth time I've had to restart for one reason or another (none of which were L3DT's fault), so in the five or six weeks I've been trying to do this, I have nothing to show for my work. Once the "step-save" feature is in, I'll try again.

Kilo

[demi]

Well, I've basically given up until the "save-as-you-go" feature is implemented. It's not the software's fault, but it's basically impossible to make the larfest terrains as-is. In the space of 2-3 months' time you can just about be sure that something is going to happen that is going to make you have to start over and lose everything you've done so far. I had L3DT running on a separate machine. This is the fourth time I've had to restart for one reason or another (none of which were L3DT's fault), so in the five or six weeks I've been trying to do this, I have nothing to show for my work. Once the "step-save" feature is in, I'll try again.

Kilo

I would ve inclined to agree Kilo. We lost power here two days in a row due to thunderstorms. I don't have aUPS and not going to invest in one right now.

Demi

[Shealladh]

Once I can get a chance to get back to my project, I too would like such a feature. So consider this signed

[Aaron]

Hi All,

Okay, I'm re-organising my dev plan to make this happen sooner (in v2.5a or 2.5b).

Best regards,
Aaron.

[demi]

Thanks Aaron,

IMHO the inclemental saves would be a major feature to the program. Loss of a few hours is a lot better than a loss of days of work.

Demi

[dennis]

My experience has been that a 16k x 16k heightfield (256 megpx) will choke Atlas on a 2GB computer during the geometry atlas file creation. At that size Atlas will need 1.25 GB of ram for calculations. True, there should be enough virtual memory but Windows generally (in my experience) disagrees. Either way a 32 bit pc can't allocate enough memory to run terrains that large. As I recall you need 5 bytes of storage space plus memory for the program to create the terrain geometry atlas.

[demi]

If you do not break the map into mosaic, yes 32 bit OS will choak. I have done 2 giga pixel maps with mosaics using XP.