Questions about Megaterrain VS. Atlas
by Pete Mickelonis · in Torque Game Engine Advanced · 04/30/2008 (6:18 pm) · 8 replies
First off, I'm a noob, so please forgive the noobish questions, but we all have to start somewhere right?
I am having a hard time understanding how terrain works in TGEA. So, I am going to list a few questions and if someone would be so kind as to answer them, that would be great.
1. MegaTerrain is the name for the "in game" map editor, True or False? (I think this is true)
2. Atlas2 is the name of the engine that allows you to import maps and such created from third party applications like L3DT, True or False? (thus no "in game" editing once the map is imported)
3. Megaterrain is the name for the terrain editor in TGEA as of release 1.7 (true or false)
4. Megaterrain means there are four terrains that you can stitch together and this ability is specifically due to 1.7 release and was not available before 1.7 of TGEA (true of false)
5. Is there any way to create maps with L3DT and import them using Megaterrain and "not" atlas? This way I can edit them in real time after they are imported using the "in game" brushes.
6. Is there ANY guide out there that explains the terrain editor for TGEA and how you actually have four terrain blocks instead of just one?
7. (this question is similair to question #5) If I use L3DT am I stuck with using Atlas or are there ANY benefits from L3DT that can be used in Megaterrain?
8. I have heard that Atlas is good for HUGE maps. This really is the way I would like to go. Thus, I would like it to take over an hour of "walking" for one character to get to the other side of the map. And if I'm understanding Atlas right in the sense that it caches map data to the disk and dynamically loads it as the character progresses across the map, this is DEFINETLY the way I would like to go... I just don't know where to start.
9. Can I still use "zoning" if I use Atlas? Or is this question completely irrelevant to this post?
Thank you so much for reading and taking the time to answer these questions...
I look forward to sharing knowledge with the community. You can be rest assured I will be writing a comprehensive Atlas guide after I figure all of this out.
-Pete
I am having a hard time understanding how terrain works in TGEA. So, I am going to list a few questions and if someone would be so kind as to answer them, that would be great.
1. MegaTerrain is the name for the "in game" map editor, True or False? (I think this is true)
2. Atlas2 is the name of the engine that allows you to import maps and such created from third party applications like L3DT, True or False? (thus no "in game" editing once the map is imported)
3. Megaterrain is the name for the terrain editor in TGEA as of release 1.7 (true or false)
4. Megaterrain means there are four terrains that you can stitch together and this ability is specifically due to 1.7 release and was not available before 1.7 of TGEA (true of false)
5. Is there any way to create maps with L3DT and import them using Megaterrain and "not" atlas? This way I can edit them in real time after they are imported using the "in game" brushes.
6. Is there ANY guide out there that explains the terrain editor for TGEA and how you actually have four terrain blocks instead of just one?
7. (this question is similair to question #5) If I use L3DT am I stuck with using Atlas or are there ANY benefits from L3DT that can be used in Megaterrain?
8. I have heard that Atlas is good for HUGE maps. This really is the way I would like to go. Thus, I would like it to take over an hour of "walking" for one character to get to the other side of the map. And if I'm understanding Atlas right in the sense that it caches map data to the disk and dynamically loads it as the character progresses across the map, this is DEFINETLY the way I would like to go... I just don't know where to start.
9. Can I still use "zoning" if I use Atlas? Or is this question completely irrelevant to this post?
Thank you so much for reading and taking the time to answer these questions...
I look forward to sharing knowledge with the community. You can be rest assured I will be writing a comprehensive Atlas guide after I figure all of this out.
-Pete
#2
TerrainBlock is the older terrain system that shipped with Tribes 2 and Torque. It allows in-game realtime terrain editing and has the ability to repeat itself over and over off into infinity (for games that only need a small play area but want to provide the illusion of a much larger world. It is limited to blended textures only and does not support applying a single large texture across the entire block. It will also repeat any shadows baked into it from buildings over and over and the repeating tiles and will not bake in shadows for buildings outside of the original square. Traditionally it has also been hard to achieve a high texture resolution on TerrainBlocks but that should be a lot better with TGEA 1.7.0.
Atlas is a separate terrain system that was designed with simulations and flight sims in mind. It allows both blended textures and unique textures (one large texture). However, it will only bake in the building shadows on blended textures since it assumes that a unique texture has its own shadows baked into it. Atlas also supports paging the geometry and textures off your hard drive as you move around the scene giving it a low memory footprint and allowing for theoretically infinite unique terrain. This is basically how the terrain/meshes in MMOs that never have loading screens work. Atlas can only be edited externally to your game in a non-realtime fashion. There are a number of good terrain editing programs available (L3DT, Grome, Terragen, etc) so you do have some options. You would use these similar to how you use a modelling application in that you generate you mesh/terrain, export, load into the engine, see if it looks right, then go back to to the tools to make the change, and repeat. This is slower than the in-game editing of TerrainBlock but it does allow for much nicer terrains and terrain textures.
With all of that in mind let me see if I can address some of your questions:
1. MegaTerrain is the name for the "in game" map editor, True or False? (I think this is true)
False. See the more detailed explanation above.
2. Atlas2 is the name of the engine that allows you to import maps and such created from third party applications like L3DT, True or False? (thus no "in game" editing once the map is imported)
True. Also more detail above.
3. Megaterrain is the name for the terrain editor in TGEA as of release 1.7 (true or false)
False. MegaTerrain is a specialized Mission Editor object designed to ease stiching together 4 TerrainBlocks.
4. Megaterrain means there are four terrains that you can stitch together and this ability is specifically due to 1.7 release and was not available before 1.7 of TGEA (true of false)
True.
5. Is there any way to create maps with L3DT and import them using Megaterrain and "not" atlas? This way I can edit them in real time after they are imported using the "in game" brushes.
Yes. You can export a heightmap from L3DT as a PNG and use that when you are creating the MegaTerrain so that it will mimic your geometry in L3DT (I believe I saw another thread that spoke about the specific settings for this). You will have to reapply the texturing yourself. You would then be able to edit that geometry in-game in realtime.
6. Is there ANY guide out there that explains the terrain editor for TGEA and how you actually have four terrain blocks instead of just one?
There is a brief discussion of this in the TGEA 1.7.0 Official Docs that ship with TGEA.
7. (this question is similair to question #5) If I use L3DT am I stuck with using Atlas or are there ANY benefits from L3DT that can be used in Megaterrain?
Currently the in-game realtime Terraformer tool is disabled. This tool performs a lot of the same functionality as L3DT when it comes to generating the terrain mesh (fractals, erosion, etc). I am hoping to have that back in for TGEA 1.7.1 but I can't promise that. For now L3DT is your best bet for generating that initial mesh.
8. I have heard that Atlas is good for HUGE maps. This really is the way I would like to go. Thus, I would like it to take over an hour of "walking" for one character to get to the other side of the map. And if I'm understanding Atlas right in the sense that it caches map data to the disk and dynamically loads it as the character progresses across the map, this is DEFINETLY the way I would like to go... I just don't know where to start.
If you specify a squareSize of 32 when you are creating a MegaTerrain it can create a pretty big map (16km x 16km). I attempted to walk and jet across this with the Spacesuit model in the T3D GameExample and gave up after 20 mins (I was just over half of the way across). With some careful tuning of the Player size and speed you could easily push this out to an hour. There are a few drawbacks though. Your memory footprint is going to be larger than the equivalent Atlas terrain since all four TerrainBlocks would be loaded at the same time as opposed to the paging that occurs with Atlas. Also, the equivalent Atlas terrain is going to render faster than 4 TerrainBlocks and use less CPU. Finally, a squareSize of 32 means that you won't have as fine tune control over the mesh and textures of the terrain that you are editing since it spreads out the edit points. You will also have to increase the size of your textures to get the equivalent resolutions.
This is a workable solution but it may not be ideal (depends largely on your needs). If you are wanting a truly *huge* terrain or seamless world then you probably do want to use Atlas. As far getting started I would highly recommend reading the Atlas section of TDN. Some of the information there is a little out of date but it is all fairly useful.
9. Can I still use "zoning" if I use Atlas? Or is this question completely irrelevant to this post?
You can still use zoning with Atlas. One of the benefits of Atlas is that you don't *have* to use zoning unless you want it specifically as a game mechanic.
04/30/2008 (9:12 pm)
MegaTerrain is a way to stitch 4 TerrainBlocks together seamlessly into a much larger terrain than the original 2km x 2km TerrainBlock.TerrainBlock is the older terrain system that shipped with Tribes 2 and Torque. It allows in-game realtime terrain editing and has the ability to repeat itself over and over off into infinity (for games that only need a small play area but want to provide the illusion of a much larger world. It is limited to blended textures only and does not support applying a single large texture across the entire block. It will also repeat any shadows baked into it from buildings over and over and the repeating tiles and will not bake in shadows for buildings outside of the original square. Traditionally it has also been hard to achieve a high texture resolution on TerrainBlocks but that should be a lot better with TGEA 1.7.0.
Atlas is a separate terrain system that was designed with simulations and flight sims in mind. It allows both blended textures and unique textures (one large texture). However, it will only bake in the building shadows on blended textures since it assumes that a unique texture has its own shadows baked into it. Atlas also supports paging the geometry and textures off your hard drive as you move around the scene giving it a low memory footprint and allowing for theoretically infinite unique terrain. This is basically how the terrain/meshes in MMOs that never have loading screens work. Atlas can only be edited externally to your game in a non-realtime fashion. There are a number of good terrain editing programs available (L3DT, Grome, Terragen, etc) so you do have some options. You would use these similar to how you use a modelling application in that you generate you mesh/terrain, export, load into the engine, see if it looks right, then go back to to the tools to make the change, and repeat. This is slower than the in-game editing of TerrainBlock but it does allow for much nicer terrains and terrain textures.
With all of that in mind let me see if I can address some of your questions:
1. MegaTerrain is the name for the "in game" map editor, True or False? (I think this is true)
False. See the more detailed explanation above.
2. Atlas2 is the name of the engine that allows you to import maps and such created from third party applications like L3DT, True or False? (thus no "in game" editing once the map is imported)
True. Also more detail above.
3. Megaterrain is the name for the terrain editor in TGEA as of release 1.7 (true or false)
False. MegaTerrain is a specialized Mission Editor object designed to ease stiching together 4 TerrainBlocks.
4. Megaterrain means there are four terrains that you can stitch together and this ability is specifically due to 1.7 release and was not available before 1.7 of TGEA (true of false)
True.
5. Is there any way to create maps with L3DT and import them using Megaterrain and "not" atlas? This way I can edit them in real time after they are imported using the "in game" brushes.
Yes. You can export a heightmap from L3DT as a PNG and use that when you are creating the MegaTerrain so that it will mimic your geometry in L3DT (I believe I saw another thread that spoke about the specific settings for this). You will have to reapply the texturing yourself. You would then be able to edit that geometry in-game in realtime.
6. Is there ANY guide out there that explains the terrain editor for TGEA and how you actually have four terrain blocks instead of just one?
There is a brief discussion of this in the TGEA 1.7.0 Official Docs that ship with TGEA.
7. (this question is similair to question #5) If I use L3DT am I stuck with using Atlas or are there ANY benefits from L3DT that can be used in Megaterrain?
Currently the in-game realtime Terraformer tool is disabled. This tool performs a lot of the same functionality as L3DT when it comes to generating the terrain mesh (fractals, erosion, etc). I am hoping to have that back in for TGEA 1.7.1 but I can't promise that. For now L3DT is your best bet for generating that initial mesh.
8. I have heard that Atlas is good for HUGE maps. This really is the way I would like to go. Thus, I would like it to take over an hour of "walking" for one character to get to the other side of the map. And if I'm understanding Atlas right in the sense that it caches map data to the disk and dynamically loads it as the character progresses across the map, this is DEFINETLY the way I would like to go... I just don't know where to start.
If you specify a squareSize of 32 when you are creating a MegaTerrain it can create a pretty big map (16km x 16km). I attempted to walk and jet across this with the Spacesuit model in the T3D GameExample and gave up after 20 mins (I was just over half of the way across). With some careful tuning of the Player size and speed you could easily push this out to an hour. There are a few drawbacks though. Your memory footprint is going to be larger than the equivalent Atlas terrain since all four TerrainBlocks would be loaded at the same time as opposed to the paging that occurs with Atlas. Also, the equivalent Atlas terrain is going to render faster than 4 TerrainBlocks and use less CPU. Finally, a squareSize of 32 means that you won't have as fine tune control over the mesh and textures of the terrain that you are editing since it spreads out the edit points. You will also have to increase the size of your textures to get the equivalent resolutions.
This is a workable solution but it may not be ideal (depends largely on your needs). If you are wanting a truly *huge* terrain or seamless world then you probably do want to use Atlas. As far getting started I would highly recommend reading the Atlas section of TDN. Some of the information there is a little out of date but it is all fairly useful.
9. Can I still use "zoning" if I use Atlas? Or is this question completely irrelevant to this post?
You can still use zoning with Atlas. One of the benefits of Atlas is that you don't *have* to use zoning unless you want it specifically as a game mechanic.
#3
@mb and Matt,
Thank you for taking the time to type all of that I really do appreciate it. You helped me gain some foundation knowledge of the differences of Megaterrain and Atlas.
Also, the fact that the terraformer is currently disabled... Man, I was looking all over for it and felt like a noob. Nobody in chat last night seemed to know either. I'm glad you mentioned that as well.
Again, thank you for your replies!
-Pete
04/30/2008 (10:04 pm)
Brilliant replies! @mb and Matt,
Thank you for taking the time to type all of that I really do appreciate it. You helped me gain some foundation knowledge of the differences of Megaterrain and Atlas.
Also, the fact that the terraformer is currently disabled... Man, I was looking all over for it and felt like a noob. Nobody in chat last night seemed to know either. I'm glad you mentioned that as well.
Again, thank you for your replies!
-Pete
#4
05/05/2008 (2:11 am)
Quote:Atlas also supports paging the geometry and textures off your hard drive as you move around the scene giving it a low memory footprint and allowing for theoretically infinite unique terrain.There is a big "gotcha" with Atlas and really giant terrains. Atlas does a great job of paging the geometry and the texture information, but the collision mesh for the geometry is still loaded entirely into memory when the terrain object is loaded. Until that is changed in the code, the terrain still has a severe limitation.
#5
This can be added to the TGE terrain, but it is hard to get enough resolution to be nice at 2x2km.
We use it sometimes to lay Digital Raster Graphics (USGS contour maps) and Digital Orthophoto Quadrangles (georeferenced aerial photographs) onto real world derived terrain height bitmaps.
05/05/2008 (3:04 am)
Quote:It is limited to blended textures only and does not support applying a single large texture across the entire block.
This can be added to the TGE terrain, but it is hard to get enough resolution to be nice at 2x2km.
We use it sometimes to lay Digital Raster Graphics (USGS contour maps) and Digital Orthophoto Quadrangles (georeferenced aerial photographs) onto real world derived terrain height bitmaps.
#6
05/09/2008 (2:10 pm)
@mark : How severe is the limitation in Atlas due to the collision mesh being loaded? At what size terrain does it become noticeable? And, off topic, is there an actual limit to the terrain size that can be generated in L3dt and used in Atlas? 
#7
- Size limitations due to collision mesh
In fact, it's not just the collision mesh but rather the entire finest LOD that Atlas keeps in memory all the time (the collision data depends on the raw vertex data). This means that basically Atlas will keep the entire terrain plus some lower-resolution chunks in-core giving it a pretty solid memory footprint.
It won't be the full AxA mesh you're exporting from the terrain program since the generators will decimate the mesh based on your specified error tolerance. I think, with a pretty high tolerance on a 4k terrain, you can expect a footprint of about 100MB for Atlas.
- Limit on terrain size
In my experience, the bottleneck here will be your terrain tool rather than Atlas. Generating large and high-quality terrain datasets is *SLOW*. L3DT, for example, has really good paging support but rendering times will quickly become prohibitive. I recently tried generating a 16k texture on a 4k terrain and it took L3DT over one and a half week.
Atlas itself does have a tree depth limit (don't remember the exact number off the top of my head; think it was 16 or something) and a vertex/triangle count limit on chunks (both 16bits). This puts a limit on the geometric complexity of your terrain, but it's definitely enough to do some insanely large and detailed terrain in game.
However, both the always-on nature of leaf chunks and the fact that Atlas uses 32bit file offsets (restricting Atlas files to 4GB) will put some practical limits on how big your Atlas terrain can get.
05/27/2008 (9:19 pm)
Kind of late to tune in but anyways...- Size limitations due to collision mesh
In fact, it's not just the collision mesh but rather the entire finest LOD that Atlas keeps in memory all the time (the collision data depends on the raw vertex data). This means that basically Atlas will keep the entire terrain plus some lower-resolution chunks in-core giving it a pretty solid memory footprint.
It won't be the full AxA mesh you're exporting from the terrain program since the generators will decimate the mesh based on your specified error tolerance. I think, with a pretty high tolerance on a 4k terrain, you can expect a footprint of about 100MB for Atlas.
- Limit on terrain size
In my experience, the bottleneck here will be your terrain tool rather than Atlas. Generating large and high-quality terrain datasets is *SLOW*. L3DT, for example, has really good paging support but rendering times will quickly become prohibitive. I recently tried generating a 16k texture on a 4k terrain and it took L3DT over one and a half week.
Atlas itself does have a tree depth limit (don't remember the exact number off the top of my head; think it was 16 or something) and a vertex/triangle count limit on chunks (both 16bits). This puts a limit on the geometric complexity of your terrain, but it's definitely enough to do some insanely large and detailed terrain in game.
However, both the always-on nature of leaf chunks and the fact that Atlas uses 32bit file offsets (restricting Atlas files to 4GB) will put some practical limits on how big your Atlas terrain can get.
#8
Bottom line: Atlas has some very real limitations to it, and any claims that it is "limited only by disk size" need to be taken with a grain of salt.
05/27/2008 (10:52 pm)
We had a terrain generated from an 8192 height map at a square size of 4 (a 32k x 32k terrain) and you needed 2GB of RAM to run it smoothly. It really started to choke as soon as we started to put any amount of objects on the terrain. However, at the time most of those objects didn't have proper LOD so I don't know how much of a "valid" test that is.Bottom line: Atlas has some very real limitations to it, and any claims that it is "limited only by disk size" need to be taken with a grain of salt.
Torque 3D Owner mb
2. Atlas is another terrain type which is basically a model in-game and as such can't be edited in-game. Also L3DT and other terrain generators can export Atlas terrains.
3. False.. but Megaterrain did come out in TGEA 1.7.
4. True. See #1.
5. Yes. Make a 512 heightmap in L3DT and import using megaterrain. Thinking about it now, you probably could create mosaic heightmap of size 512 and import each one and place them.
6. Having 4 terrain blocks is basically the same as having one. The older books cover editting legacy terrain, and the new docs with tgea cover editting terrain. The legacy terrain is editted the same basically as the meg terrain.
7. see #5.
8. L3DT is good start, and there's other programs which cost more that can be used.
9. Zoning... as in using triggers to load another map? Sure you can.