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Rock Modelling


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Hi,

I'm working on a Grand Canyon terrain for a school project. I've already generated the base of the terrain using a height map painted in photoshop.

What I need to do now is to model rock structures as extra details to be applied onto the terrain. (Which cannot be done using heightmaps)

My aim is a create a digital asset which allows the user to generate rocks of different shapes and sizes.

My client wants the rock structures to be shaped like the ones shown in the attached reference image.

One of my lecturers advised me to start with metaballs.

Does anyone have other ideas on how to start off?

Attached files are: Screen shot of the terrain I've generated and the reference image my client has provided.

post-6570-130130069994_thumb.png

post-6570-130130075107_thumb.jpg

Edited by Crapbox
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For the level of detail that you have in the matte painting I would recommend working on individual separate chunks rather than trying to do it all in one surface. Kinda like putting different pieces of a puzzle together.

It will make your life a lot easier when it comes to texturing and repositioning to adjust the landscape for your desired composition.

I would start with basic polygonal shapes (not really metaballs as their geometry is pretty useless when you want to subdivide them). Make basic shapes (spikes, the semi-arc, perhaps a more plateau like fracture plate). Then use vop sop with various noise patterns (remapped noise, exponential noise, different levels of frequency and magnitude) to layer the detail by displacing your geometry. You could mix in bits of texture too. Perhaps research a bit on erosion patterns.

In regards to the rocks, it's the same approach, just use basic boxes or low resolution spheres as starting objects. I would also consider scattering them over the terrain and rendering them as delayed load instances (have a look on my blog if you don't know how to do that), because you might need a lot to make it look good.

Some shapes do create a specific silhouette, so you might want to model them a bit more detailed. If it is your goal as an exercise to be more procedural than using metaballs and volumes will probably give you interesting results too. But you will still need basic shapes/pointclouds to define the area where you want to copy the metaballs or where you want to read in the volume.

The geometry with the heightmap can be used to sit behind some of those chunks... almost as if it is the sand/dirt in which the massive rock pikes are sticking out from.

You blend the two through adding bits of rock, vegetation (even if it's dead), other props you have sticking in the ground, shading (occlusion pass, potentially remapped to reveal different material -> wear), and add a fog volume to get that hazy feel.

In regards to being creative with rocks. Do a search for Macha's rock thread.

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For the level of detail that you have in the matte painting I would recommend working on individual separate chunks rather than trying to do it all in one surface. Kinda like putting different pieces of a puzzle together.

It will make your life a lot easier when it comes to texturing and repositioning to adjust the landscape for your desired composition.

I would start with basic polygonal shapes (not really metaballs as their geometry is pretty useless when you want to subdivide them). Make basic shapes (spikes, the semi-arc, perhaps a more plateau like fracture plate). Then use vop sop with various noise patterns (remapped noise, exponential noise, different levels of frequency and magnitude) to layer the detail by displacing your geometry. You could mix in bits of texture too. Perhaps research a bit on erosion patterns.

In regards to the rocks, it's the same approach, just use basic boxes or low resolution spheres as starting objects. I would also consider scattering them over the terrain and rendering them as delayed load instances (have a look on my blog if you don't know how to do that), because you might need a lot to make it look good.

Some shapes do create a specific silhouette, so you might want to model them a bit more detailed. If it is your goal as an exercise to be more procedural than using metaballs and volumes will probably give you interesting results too. But you will still need basic shapes/pointclouds to define the area where you want to copy the metaballs or where you want to read in the volume.

The geometry with the heightmap can be used to sit behind some of those chunks... almost as if it is the sand/dirt in which the massive rock pikes are sticking out from.

You blend the two through adding bits of rock, vegetation (even if it's dead), other props you have sticking in the ground, shading (occlusion pass, potentially remapped to reveal different material -> wear), and add a fog volume to get that hazy feel.

In regards to being creative with rocks. Do a search for Macha's rock thread.

Thank you for the detailed advices! I'll try them out today as yesterday I was busy with an interview. I'll post questions if I've got any problems later on.

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you may also want to look at Terragen to build the base shape - the into Houdini for the rocks and ectra details...

Ah yes! My teammate and I were looking for this software but we didn't know the name of it. Thank you!

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