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I'm currently trying out displacement maps. As I was told by some video tutorials I need to apply them as a (displacement) modifier on the mesh. Therefore, I have to subdivide the mesh to achieve more detail. These subdivided mesh is then stored in my blender file, making it very huge. And also blender eats up a lot of memory...

What I'm looking for is some kind of virtual subdivision function which doesn't actually store the vertexes, which are only displaced by the displacement modifier. So they are actually reconstructible by having the number of subdivisions and the displacement map available. It would also be nice if I could disable the subdivisions visibility for some objects during work and only render them in high detail.

Also, blender v2.76 seems to crash sometimes when having too many subdivisions for a quite simple plane (scaled to 7x7 units, subdevided by factor 100 and then again by factor 3). While I have 16 GB of RAM installed in my machine... Any Idea how to reduce this?

Additional Info:

As I was suggested to use the subsurf modifier, I looked (again) through the list, but wasn't able to find it. I know I have used it some years ago, when I worked through some blender tutorials... Has it's name been changed? Where is the subsurf modifier?

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    $\begingroup$ You can use a subsurf modifier $\endgroup$
    – user1853
    Commented Dec 6, 2015 at 23:55
  • $\begingroup$ You could, maybe, use normal maps, although those are kinda different $\endgroup$
    – someonewithpc
    Commented Dec 6, 2015 at 23:56
  • $\begingroup$ @cegaton: Seems to be a good answer... Please leave a screen shot to see, where to find this modifier. Haven't found it, thought. $\endgroup$
    – SDwarfs
    Commented Dec 7, 2015 at 0:01

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Using a subsurf (subdivision surface) modifier before the displacement will give you a lot of flexibility.

enter image description here

Here's a simple plane (imported with the images as planes plugin) subdivided 100 times in edit mode, and then with a subsurf modifier added to it...

enter image description here (Click on the images to enlarge)

The main advantage of the modifier is that you can determine different levels of subdivision for the 3D viewport and for the final render, so you can keep a decent level of detail for the final render, while having a responsive interface...

The order of the modifiers is important here because you want to subdivide first and displace later, otherwise you'll have a much smoother map but with less detail, like illustrated here:

enter image description here

To change the order of the modifier stack, use the triangles on the right side of the modifier's window:

enter image description here

A happy medium is using a subsurf before displace modifier and then one after:

enter image description here

But be extremely careful!: by doing that you are making an exponentially large number of vertices.

For example: If you set the first modifier with a subdivision level 2, it will create 25 vertices out a single quad. Further subdividing those 25 quads with other subsurf modifiers can very quickly take you to a number your computer will not be able to manage, and might even make it crash...

Please read this performance considerations: https://blender.stackexchange.com/a/15667/1853

To get to very detailed but efficient mesh, you can get to the level of detail you want with the subsurf modifiers, apply them (use the apply button on the modifier), and then use a decimate modifier to make the number of vertices more manageable while keeping the shape.

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  • $\begingroup$ Could you give a step by step guide please, how to find the option for the subsurf modifier, please? What I can find is only the "Subdivision Surface" modifier. $\endgroup$
    – SDwarfs
    Commented Dec 7, 2015 at 0:06
  • $\begingroup$ Ok, "Subdivision Surface" seems to be exactly what you meant... and the "subsurf" is a special type of it. However, it's limited to only 11 subdivisions. Is there a good reason for subdividing the plane before applying the subsurf modifier? Wouldn't applying just a subsurf modifier be better (e.g. multiple times 11x)? $\endgroup$
    – SDwarfs
    Commented Dec 7, 2015 at 0:13
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    $\begingroup$ do not go over 2 or 3 subdivisions! While virtually for now, the modifier will create new geometry and that will have a huge impact of your machine being able to deal with such a large number of verices $\endgroup$
    – user1853
    Commented Dec 7, 2015 at 0:18
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    $\begingroup$ "Subsurf" is just the slang for "Subdivision Surface". $\endgroup$
    – Ray Mairlot
    Commented Dec 7, 2015 at 1:48
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    $\begingroup$ The hint about the decimate modifier was very very helpful to me! This way I can push the resolution of the mesh up, displace it with high detail and then reduce its complexity. Very nice! $\endgroup$
    – SDwarfs
    Commented Dec 7, 2015 at 2:49

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