Hi Keith - here's an example showing the difference that using vertex normals will make - I loaded your Crab.3dm file and exported it out using the exact same settings you show above (the somewhat coarse default angle = 12), and loaded it into Cinema4D and rendered it there - notice that all of those glitches that you pointed out on the claw are completely gone with the same polygon mesh density.

If you want to get better looking results you will need to use a rendering tool that works better with CAD originating data and can load all the information from the .obj file including vertex normals rather than skipping the vertex normals and just having them created by averaging polygon faces which is what creates those glitches that you pointed out above. Simlab composer would be good choice to use because it's pretty easy to use and not as expensive as many of these other fancier rendering and animation packages.

Anyway here's what your same data (with same density as you used above) looks like rendered in Cinema4D:



- Michael

Hi keith, just one more note about this part:

> The model I copied on turbo squid http://www.turbosquid.com/3d-models/3d-model-cartoon-crab/822724
> has only 5,646 polygons and looks very smooth.

That's 5,646 polygons for the "base mesh" - that model was created using a technique called "subdivision surfaces" and the super smooth render that you see is because of additional polygons being added just for the rendering process.

That particular type of modeling method also called "sub-d modeling" is set up like that where you have a coarser control mesh and then a smoothed down result that adds more polygons when it's rendered. It's a different type of model structure than what you will get with a CAD model.

If you wanted to specifically make something with a low polygon count that used that same process you would need to model it in a polygon modeling tool by manipulating cage points, it's a different way to create models than the curve oriented CAD method that MoI is based on.

The models that you build with MoI and export as polygons will not be further refined just at render time by the rendering program, so because of that if you want them to have a smooth looking silhouette you will need to generate them with more polygons in them when you save them out from MoI.

- Michael

Hi Michael
>If you wanted to specifically make something with a low polygon count that used that same process you would need to model it in a polygon >modeling tool by manipulating cage points, it's a different way to create models than the curve oriented CAD method that MoI is based on.

A couple of last questions if you have the time.

1. Once you had loaded, for example, my crab into C4D could you then have converted it to a subd model or is there something about the mesh that Moi makes that is fundamentally different to the mesh made in a native subd modeling program?

2. If I made a model with a lovely render with moi + Simlab and put the OBJ on Renderosity. Do you think people would curse me for wasting their time because the model was not made in a subd or polygon modeling program?

I'm tempted to buy Simlab and will definitely try it out.
Regards
Keith

Hopefully I can save Michael some keystrokes.

1. No, you cannot change a MoI OBJ into a SubD model. There are tools called retopology which can help this, but mostly it's a tedious process.

2. AFAIK, there are no problems sellling on Rendo or other forums a NURBS based topology model vs a SubD one. I used to sell a bunch of stuff on Cornucopia (another Rendo like marketplace) and none of it was SubD. In fact, I would wager most of the content on Rendo is NOT SubD.

Vitaly Bulgarov sells a bunch of SubD and non-SubD models at his kitbash store:
http://vitalybulgarov.com/3d-kitbash/

Some of the models were created in MoI:
http://vitalybulgarov.com/3d-kitbash/black-widow-attachment-blocks-pack

Here's a wire for the same set and is a good example of the mesh options density which works well in poly renderers (click to enlarge):

Hi keith, just one additional comment on this one:

> 2. If I made a model with a lovely render with moi + Simlab and put the OBJ on Renderosity.
> Do you think people would curse me for wasting their time because the model was not made
> in a subd or polygon modeling program?

Like Chipp said, I don't think so but it might be a good idea to include a shot of the wireframe as well just to make it clearer.

You also wouldn't want to claim that the model was something like "ready to animate", when someone is trying to use the model for an animation for something other than rigid body motion, like if they want it to walk around with flexing limbs and stuff like that, that's when a sub-d created model is helpful.

Other than that particular kind of flexing animation you would not want to be so worried so much about a low polygon count like you seem to be, for a static render you would actually want a higher polygon so it looks smooth. A low polygon count is usually only specifically desirable for a sub-d type model, especially one that will be animated, or for models that will be used in real-time game engines. For models that will be used in rendering you should not be so worried about it.

Also some rendering programs can have difficulty dealing with n-gons so for widest compatibility you'd probably want to export with "Output: Quads & Triangles" rather than "Output: N-gons", or maybe include both types.

- Michael

If you only have Carrara and only want to render the model, you can save it as a sat or a step and use Carrara's meshing parameters to get a nice result. If you want to first create the OBJ's, then MoI's mesher will be much better, but as mentioned, Carrara has done something with the OBJ importer....

Hi everyone
Thanks for being so helpful. I learned more today than I would in weeks of trawling as when I do a search its just chance that some answered my question in the past. I used SimLab and all the things I have discarded look a lot better than I thought possible, and where there are problems I can understand why; in most cases at least.

Chipp the stuff you posted really helped too and has given me some perspective. A lot of you who have spent a career doing this stuff amaze me because you know and do things I don't even know are possible.

BurrMan, I stumbled across people talking about Daz turning towards selling assets and no longer supporting Carrara, which if true makes me sad. It does a huge amount of stuff but the renders I can produce (that looked cool to me when I started) are poor compared to the ones regularly posted here. When Michael told me about the problems with smoothing I upgraded to 8.5 and found the import of 3dm to be present but had no better smoothing than the standard version. I assume that there are more people who want and are able to pose girls in bikinis with hefty swords than people who want to make models. My guess is that Cararra is going to be just another way of posing genesis and 89.7 smoothing (or whatever it is) works best.

To be honest I'm well into uninformed speculation now so will leave you all in peace until my next ill informed venture causes me difficulty.
Many thanks
Keith

Hi Kieth,
So just a couple last additions here, since it can help you with the NURBS and Poly's differences you are discussing.

(And my comments will be in regard to the NURBS we are starting with in MoI)

Most importantly, when you are bringing in you model to a poly/rendering application, anything you see referencing "Smoothing", will be throwing out what Michael referred to about "Vertex Normals"... (These are very important to your CAD (NURBS) model going into these other arenas ) If they are not being read in, then that will self destruct your CAD data.

""""""""""It does a huge amount of stuff but the renders I can produce (that looked cool to me when I started) are poor compared to the ones regularly posted here""""""""

Well, remember you are looking at people very skilled at doing that..... Some of the renders you see in the MoI Gallery are from "Carrara"...... Simlab is a great choice though, like some of the others. They are geared towards creating great looking renderings with very little input. But you sacrifice from some of the other programs like Carrara, which allow you to have control very deep into the render.... (I keep mentioning Carrara because you mentioned it. Like you have noted, the development is not really going to keep up. Something like Modo would be far superior....)
But having very deep control of the render can be not so good for someone starting out... If you don't set all those parameters well, then the render will suffer.

You mentioned earlier about a guy's challenge to "show your polygon" or something like that... The simple answer is we don't have "polygons" in NURBS, but we can create them from our NURBS objects.

Thanks BurrMan
I get what you say, I hope. I like nurbs but coming at it from an uninformed direction did not really understand why there were several types of modeling. You have all helped m understand something that to most people is very specialist knowledge. I have HUGE respect for you all and have been trying to explain to my wife, a psychologist, how you all make things out of maths, points and lines. I think she humors me:)
Keith

Hi Keith1961 from Mauro(1962) :)
talking about Moi mesher to obtain a good export it depend also what tools you use
let me show few example,pictures talks better than my english ;)

an egg shape obtained first with a revolve,then from solid, extracted isocurves for loft and add two points at the poles





now exporting you can see little differences between them, a better sudbivision for loft at the pole area




now a wavy surface using same extracting method:sweep and network




again little differences, better regular subdivision on the network




the egg should be done obviously using revolve but if you don't need an accurate shape,it can be done using loft because of better subdivision at the poles
it's better to export with the good foot before render ;)

M

Hi Mauro - yes the different UV surface structure of different construction mechanisms can have an effect on meshing.

But the differences you show there are very minimal - the one for Sweep versus Network probably has more to do with using the "aspect ratio limit" parameter - it's just a matter of luck that the sweep is very slightly shorter in length (as traveled along the surface because of slightly different shaping) than the Network and so the polygons near the border are just under that limit while the Network one are just very slightly over it. If you change that parameter slightly to different values like 1.8, 1.9, 2.1, 2.2, etc... you should be able to arrive at the same result for either one of those surfaces. I rarely use the aspect ratio limit myself, usually the distance-based "Divide larger than" parameter has a more uniform effect.

For the Revolve versus Loft, there will can be slight differences depending on the control point spacing on your revolve profile versus the spacing of the sections for the Loft.

I would recommend not really worrying so much about these kinds of very minimal differences - if you need that extreme level of control over the polygon output like more polygons in just one single spot and not in other areas, you are probably better off building the entire shape in a polygon modeler from the beginning rather than generating polygons through any automatic process at all...

For normal use, if you don't have enough polygons in a particular area like the pole, just move the angle slider towards the "more polygons" side until you have enough, just don't worry so much about having a few more in other areas as well. If you have shallow curvature then the slider alone may not give enough detail since it's based on curvature - to make shallowly curved areas to have a higher density use the "Divide larger than" option as well to break down any large polygons to a more uniform size.

If you want to post your 3DM model files for those cases, I can try to show what mesh settings to use to get good output for each of those cases that will look exactly the same as each other when rendered.

- Michael

Hi Michael
This was just a "side note"..showing this example we expand the knowledge of Moi thanks to your explanation,like in other situations.
Sorry i didn't save the file but agree with you about rendered result.

M