Scene composition

[tempaccount]

A somewhat more abstract topic, but something I've been mulling over recently. How do you approach scene composition?  I assume for aerial scenes this is a lot easier, but lets say you would like to have something interesting in the foreground of your scene. Do you build an interesting heightmap in World Machine or Geocontrol, and pinpoint your camera location in that software? Or do you rely more on luck? Do you use a lot of objects to create an interesting front?

My approaches have been rather varied - I've noticed that while it's decently easy to make things look realistic with fractals (clouds, ground), it's a lot more difficult to affect the scene composition with them.

An example: I tried to make a scene that had an big rock arch - kind of one you could see at Stonehenge. Heightmaps or displacement fractals didn't help me there, since heightmaps are only height information, and creating a fractal that produces an arch at an exact place would be overly complicated (at least for me). I tried messing around with Blender and importing a basic object into a TG2 scene and then "texturing" it there with displacement, but this wasn't a workaround as I learned - objects seem to be apart of the scene geometry somehow, and it's difficult to implement displacement and other detail into them without blowing the object geometry up.

I suppose I'll look into heightmaps once again - just for basic scene composition, and try to learn my fractals a bit better. I suppose this might be one of those lessons in humility, as well :p

[FrankB]

This is why I'm glad that I can enjoy CG as a hobby. I can do how I please, and don't have to punch TG2 into delivering an exactly pre-sketched scene.
I know what you're talking about, though. It's really tough to make procedurals give you exactly what you want, at the location you want. Sometimes it's impossible.
However, your blender object approach for an arch that you displace in TG2 might still be a good solution to the problem, but you have to be able to increase the displacement tolerance of the object, so that the seams don't break too easily. I haven't ever tried this at all, yet, personally.

Frank

[Henry Blewer]

If you are using Blender to make landscape data, you will find some problems. The object will have to be very detailed. Not necessarily to the exact shape, but so the displacements do not explode the object. I recommend that triangle faces be used. Terragen 2  does not seem to like quad based objects.
I would use the Blender object in the foreground. Have the Terragen 2 landscape in the background. This way you can avoid the possibility of having a seam where the object meets the ground.
I was thinking about how to make natural arches using Blender. I have a long render going which should be done tomorrow morning. I'll give it a try and post what I find out here.

[tempaccount]

Ah, thanks for the tip about triangles - I guess I could give it a try. By "detailed", I assume you mean an object will have a lot of polys in it?

Does the size of the object matter? My initial object was quite small, and very prone to explode with the smallest displacement. Anyway, it seems like the shadows are an another issue with big displacement in objects which might make my initial idea a fluke. It was to define the form and composition of the scene with basic objects, and throw some wild displacement into them afterwards.

With more simpler shapes, World Machine 2's layout editor has been rather effective - it's only heightfield data, but you can still define the exact composition rather easily.

I've also been thinking about using the painted shader and imagemaps to help with the composition, but that's another large topic.

[Henry Blewer]

Blender does not have actual size information. The best way to deal with Blender objects is to export them as wavefront obj files. I scale them to the proper size in Terragen 2.
If you are trying to make natural arches in Blender, then a bit of the landscape obscuring the 'ends' of the object is the way to go. And yes, when I said detailed, I meant small, tiny, triangle polys. This gives the mesh more data for the deformations, avoiding the exploding seam problem.
I just got off work. In about 3 hours I will start messing with Blender to make a descent arch. First though, I'll make the landscape it will sit in. Render a quick render at 1024 x 768 of the area I want the arch to sit. This will be used as a backdrop image for reference.

[Mandrake]

njeneg, I think what you meant to say is that tg2 does not like n-gons
Modeling with quads, is the correct way to model. A purest would say he never uses triangles, unless absolutely necessary.

[Henry Blewer]

I never bothered to learn the correct terms for things. But when dealing with displacement across different modelers/renders, the n-gon is your friend. Quads do render better and faster. I guess you could try both.

[Mandrake]

An n-gon is any poly with more then 4 vertices's (points)
And is definitely your enemy in tg2 renders.
Whole surfaces will disappear in patches or totality when viewed from any direction other then perpendicular to the camera.
Apply a displacement and you won't see it at all, most likely.
A quad is your best bet for displacement.

[reck]

njeneb, I thought I read that n-gons are coming with Blender 2.5, do you know if this is correct?

[Henry Blewer]

I have not had much time to mess around with Blender 2.5 alpha. I did not notice them in an earlier build I had.

[tempaccount]

I finally had time yesterday to mess around with your object, njeneb. Thanks, it definitely gives me some ideas and applications. Looks like applying displacement and other big features in Blender is the way to go, to make your object fit into the scene somehow - that seems to be the most difficult part. I've been trying to learn that software on my spare time.

I noticed you had textured the object in Blender, but wouldn't it have been easier to apply the same color shader to it which the cliffs on the left have?

[Henry Blewer]

I have found that giving the basic color information and materials works best, no image maps or Blender procedurals. Then when I import the object into Terragen 2, I add the procedural textures. I like to stay away from image maps to keep memory use down.