Maxwell Render

I give... call me whatever you'd like, I can't find them... help please...

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The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" but "That's funny ..."
Isaac Asimov

If you view a Displacement in the material editor, you should find at the bottom a new Type drop-down, used to set whether it uses on-the-fly, pretesselated, or one of three vector types, and also three new Scale values, which are used to control vector displacements.

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Next Limit Team

Thank you JD; as usual you are fast on the reply. I'm trying to get my head around this, and so far my results aren't great. I'm sure its something I'm doing wrong so let's start from the beginning.

I downloaded the "ROCAS" displacement from the Maxwell Resources site. It's a bunch of pebbles... the displacement map is 5.313"x5.313" so I made a plane that size as well (0.001" thick if that matters). I set "Subdivision" to 1000. Now, correct me if I'm wrong (please) but to me this is the same as (for instance) when I did this in Lightwave; you'd make the mesh with more polys to get more detail. When I leave "Type" as "On the Fly" it renders, but doesn't give a "round pebble" look like the preview shows. If I choose "Pretesselated" it crashes with a Runtime Error. Any of the other types stretch the image in all kinds of ways. Other than messing with Subdivisions and Type I din't change the material. Thoughts?

Thanks!

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The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" but "That's funny ..."
Isaac Asimov

Well, my main thought would be that I am not at all experienced with setting up the new pretesselated displacement. And, that I doubt many others are yet either, so you may want to start a new thread about it in the main Maxwell forum to get things started.

For displacement in general though, yes, the subdivision of the geometry to which it is applied matters greatly, and this is most likely why you are not getting the results you see in the preview, in the actual render. By saying 'subdivision', I am not referring to the Subdivision parameter in the UI (which was previously named Precision, I think), but to the physical makeup of the mesh being displaced. SolidWorks will probably provide you with, say, a plane made of two triangles, or something along those lines, and it will not work well at all, as there is alot of math involved in interpolating the pixels of your map over those long distances. So you want to find a way of forcing a more highly subdivided mesh to begin with, and I might assume this to be the case whether you used on-the-fly, or pretesselated. SolidWorks meshing being so primitive, though, you may need to generate this geometry in another application (you mention lightwave); I do not recall there being any tricks for telling SolidWorks to use a 'minimum edge length' or similar.

One thing I can tell you about pretesselated displacement is that it can easily eat up all the memory you've got in relatively short order. That's the whole reason why Maxwell's displacement has always been analytical; but there are not-insignificant gains to be made at render time by sparing the engine from doing all of that math, so depending on the situation, you may prefer to use one or the other. If you are running in 32-bits, I would probably recommend staying away from pretesselated, period, but that is just me -- when you run out of memory, it's game over.

As for crashing, I would be interested in knowing if you believe it to be due to out-of-memory or not. You could check that by monitoring the application (SolidWorks if you're using Fire, or maxwell.exe) in Task Manager. From what I've seen, you can pretty easily run out of memory even in a 64-bit application.

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Next Limit Team

I *thought* you were going to say that about Solidworks. I don't know a way to "force" this as well. I *used* to use a SW to OBJ converter and then bring it into Lightwave/assign materials and render. A real pain in the behind, but much more control over things. Just don't make any changes to the geometry or you get to start all over...

Test...test...test...lol.

So here's a plane with the "rock" surface and 1000 Subdivision:


And a sphere:


And the image from the Resource page:


So, the sphere looks promising, but since I have no control over normals it gets all messed up. No control over the "mesh" so the plane is a disaster. So, unless someone far more clever than me (and there are many, many of you) I see no way to use displacements usefully. I had grand ideas of displaced text on parts instead of modeled, dashed against the rocks of NURBS. Rocky NURBS? I'm glad its Friday...

Oh yeah, the crashing. It's a 32 bit machine. I have a 64 bit at home I can try it on, but as we see, not sure its worth pursuing.

EDIT: For completeness here's the sphere as mapped in SW:


EDIT EDIT: Did one one a "hemisphere". Better but pinches at the top as you'd expect...

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The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" but "That's funny ..."
Isaac Asimov

Displacement will often suffer a bit with geometry from SolidWorks, since in addition to controlling the number of divisions in the mesh, we would also like to try to keep triangles as square as possible; sometimes you might get that, while other times, you may get triangles which are long/skinny, and these will not work so well. I know that there are a number of people who use Moi 3D in conjunction with SolidWorks (Rhino too), because it has a nice mesher, and because:

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Next Limit Team

I remember Moi; I think I paid for it once... I DL'd the trial and ran the sphere through it from SW. I exported it back as a 3dm file into SW. Cranked up the image quality to "stupid" and rendered. You can see that Moi changed the normals, but did a weird thing (you can't see 'cuz its in back) where it "patched" a big section. The results are better but you can see the facets of the poly's. That's enough!

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The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" but "That's funny ..."
Isaac Asimov

Do you have Smoothing enabled in the Displacement? And what you would want to do with Moi is to cut the SolidWorks mesher entirely out of the picture by bringing the geometry back into SolidWorks as STL (make sure to select Solid Body or Surface Body, rather than Graphics Body, in the STL Options box, in the Open dialog).

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Next Limit Team

And texture interpolation: on

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If you apply it to a plane with thickness, no matter how small you'll get that double displacement like in your first render which is a lot of waste both in polys and RAM. Be careful with the subdivision setting when using pretesselated, it looks like you're running out of RAM with subdivision set to 1000 (this is really too high) on a 32b machine.

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Next Limit Team
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