Terrain modelling nightmare

[Jeff Mottle]

Why do my threads titles end in "nightmare" LOL.

 

Anyway I'm doing up a rendering for a large site and need to show the surroudding terrain. I've cleaned up all the contours, added spline normalization and made a terrain object out of it. Everything looks perfect. However the terrain model itself is about 685,000 faces and it slower than molasas to work with. Any spline modification I need to make within the terrain object take SOOOO long to take effect. Simply picking a vertice take 40-50 seconds to react.

 

Are there better ways to create my terrain from the contour lines or a better way to work with the terrain object? One thing I should mention is that becuase the contour interval is very tight, I had to set the normalize spline to 1.

 

Help!

[Ricardo Eloy]

Well, I usually do something that might sound weird at first, but found it to be really effective: Reactor. I draw all the level curves and extrude them to their heights. Then, I convert them into Poly and attach them to each other, making a unique object. Then, creat a plane over the terrain layered piece and use Reactor to have it conformed to the level curves. With that, I can get a very smooth, face-controled terrain mesh in no time. Hope it helps!

[Jeff Mottle]

Thansk Rick,

 

What exactly are you doing in reactor? What modifiers etc.

 

Cheers,

Jeff

[Ricardo Eloy]

It's quite simple:

1) Select the terrain and click the Rigid Body button on the Reactor floating bar.

2) Apply the "reactor Cloth" modifier to the plane and click the Cloth button on the Reactor floating bar.

3) Start the simulation preview and watch the plane conform to the terrain.

4) When you find it enough, stop the simulation (P), go to the Max pulldown menu of the simulation window and choose "Update Max".

5) No you're back to Max, and your plane is conforming the terrain object. Convert it to Poly and delete any unwanted faces. You might want to fix some vertexes as well.

 

Remember each terrain is different, so you may play around with weight and density settings before you get what you want.

[Jeff Mottle]

Thanks Rick, A very interesting method. Unfourtunately my contours are much too dense for this technique to work the way I want. THis looks really good for smooth, sloping hillsides and gentle terrains.

[Brian Cassil]

Are you using 2' elevation increments? If so you could try eliminating all elevation contours eccept the one a 10' increments and then set your spine normalization to something less dense. I usually try to keep the lateral vertex spacing to the average distance between spines, therefore if you eliminate some of your splines you would have a more "optimized" mesh. Of course you are losing detail but based on what I'm looking at you probably have too much detail as it is.

 

I hope this makes sense and good luck! I have certainly spent my fair share of time pulling my hair out with terrains.

[Christian Miranda]

Hi Jeff,

 

I would keep all of your splines in a group and not attached to each other. that way you can make quick edits and once you have the splines ok, you can generate the terrain at any time.

 

Btw, I hate Max´s terrain object. Form-z is the way to go for terrains. If the company that you work for does a lot of terrains, I would seriously consider form-z.

 

Regards,

 

Christian Miranda

[Frosty]

I second Christian. The Terrain tools in FormZ are spectacular.

[Chad Warner]

How about using the optimize modifier on the terrain after you create it? Either that or the multi-res modifier (not sure if max has this, but Viz does) That will get rid of any un-necessary faces.

 

-Chad

[ferox]

hi jeff

685,000 faces? too many vertices?

i would presume it's an LOD issue.

 

i'm assuming that your terrain is a triangulated network (TIN)?

 

with large terrains, i usually optimise; which generally means using a base grid with a large mesh size, say 100m x 100m, or down to 5m x 5m etc depending on the size of the site. the large terrain grid spins around easily in the viewport.

 

if more detail is required, i include another (high resolution) mesh where the detail is needed - in front of the camera.

 

at what altitude and angle is your camera panning the site? at high altitude (8,000m) you dont need over-meshed grids, just a good aerial photo drape and detailing (usually bump mapping) where required. for oblique views, let the aerial photograph create the illusion, not vertex-intense geometry.

 

i'm looking at the oblique aerial view of your attached jpg, is that broad steppe in the foreground a network of vertices, or just one plane with a bump displacement map ??

 

hope some of this helps.

[Jeff Mottle]

Thanks for all the suggestions guys I really appreciate it. Today is Canada day here so I'm not working on it, but I thought I'd point out a few items. Both I and the client like the stepped terrain look rather than the smoothed terrain so in order to get the nice detail in the background (as seen in the attached image) I need to keep the contour interval fairly high. Rigth now it is 0.5m (just under 2 feet). The final image will be very high res so I think reducing the interval to less may have a negative impact on the overal detail. I think it may be something I'll have to try though. This woudl help in the Spline normalization as well. As the interval is so small, the normalization had to be at 1 or the splines started to overlap each other.

 

ferox: I'm not quite following your suggestion there. Could you expand upon that? I don't know what you mean by "base grid". I'm using the terrain object.

 

 

Christian: My splines are all grouped together, but when you apply the terrain object, there is no way to turn the terrain off. Even goign into the spline object is still MUCH slower than going into the spline object without the terrain object applied. I wish it were like a modifier that could be turned off.

 

 

One thing that just occured to me is the possibility of using the terrain as a background image and composit the building and site, which will sit in the middle of the valley. Becuase the buillding itself will on a nearly flat graded valley floor, I could just render everything onto a matte/shadow and comp the two together later. Of course that still does not help the tweaks I need to make to the terrain object. Will have to experiment with a few of your suggestions on Friday.

[Ernest Burden III]

I second Christian. The Terrain tools in FormZ are spectacular.

 

When they work, which really when you get to the point of knowing exactly what it wants from you TO work. It's very particular, and an error will explain it like this: Can't mix entity types, error code 13.2

 

Thanks, that hep'ful.

 

Also, once the terrain is made, it can be optimized (poly reduction.

 

In my canyon animation of a few years ago I did terrains at several resolutions--sub-meter close up, about 2m middle-distance, 10m or more far off. Welding them was time consuming, but the end was manageable by the computers that had to render the frames (in the age of 1G processors).

[Jonny English]

What do you all think is the ideal tool/software for modelling terrains?

It seems as thought Max can do it, but it takes a lot of effort, a long time, and isn't that great...I would be interested to hear your upto date opinions.

[siliconbauhaus]

Jeff,

 

Have you ever considered using SketchUp for your terrain?

 

You can simply pull your contours up to the desired level then drag the rear edge of each contour to meet the front of the next. You can then draw all your roads and stuff flat, extrude it past the highest point of the terrain and use "intersect with model" et viola your roads and pavements are following your contours.

 

You can even paint the countour with a aerial photo and it will follow the terrain.

 

Rick, I'm going to have a go with reactor when I get a chance, cheers for the tip

[amarkovi]

i know this thread is old but maybe someone might use the tip:

 

to create terrain real simple in max all you have to do is create the contour lines in the plan then pull each one up to its Z coordinate then> Compound Object>Terrain.........peace of cake and works great!