Split and export to 3ds

Split and export to 3ds

I need to export a big piece to a 3ds file. The problem is caused by the size of the piece : about 150000 triangles and pieces can't have more than about 65000 triangles, in a 3ds file. I tried a boolean operation, but it gives some bad results. I also selected some parts of the piece, and used the "split" operation, to make three smaller pieces and to export to 3ds. However, the split operation gives a visible line on all the pieces, like what is shown on the sphere below. Is there a way to remove that line (the splited sphere should be smooth, like the original sphere) ?
 

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Hi,
I think there is no solution to avoid this seams if you really need .3ds files. These seams are caused by the calculation of the normals.

Alternatively you can use a file format which support more than 65k vertices per object. Like FBX or OBJ.

For what purpose do you need a ball with 150000 triangles in a .3ds file?

Bye,
Martin
 
Hi Kali.
Where you want to take your sphere to? I ask because Bryce for example just need 256 polygons for an absolut smooth ball.

With kindest regards
Frank
 
Thanks for the replies. My solution is to use .obj instead. But I don't know this format and its limitations. How can you compare it with .3ds ?
 
Thanks for the replies. My solution is to use .obj instead. But I don't know this format and its limitations. How can you compare it with .3ds ?

.obj is a ASCII file format and therefore need some more memory. But it doesn't have the 65k limitation.

Do you plan to import that file in your own app/game? If yes it might be even easier to create the mesh by yourself. Creating a ball mesh is really easy.

Bye,
Martin
 
I was supposed to send the file to someone working on a PC, and using another kind of modeler (I don't know which). And it isn't a simple sphere, but an highly deformed one (a neuron. But it's too ugly to show it here !). The problem is I don't know if his modeler can recognise .obj files.
 
Hi Martin.

The golden ball.obj comes from Cheetah3d via importer with a 16x16mesh and reached Bryce with 480 polygons. The red ball is a Bryce object with 256 polygons.

With kindest regards
Frank
 

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The golden ball.obj comes from Cheetah3d via importer with a 16x16mesh and reached Bryce with 480 polygons. The red ball is a Bryce object with 256 polygons.

Hi Frank,
that has a very simple explanation. The raytraced Bryce ball hasn't 256 polygons. Even if the UI says it. In raytracing the easiest ray intersection test is ray/ball. That is an analytic test and 100% accurate. But it only works for balls. Many raytracers handle that special case of a perfect ball. Bryce probably too. So you get a perfect smooth ball.

But OpenGL can't preview a perfect ball. OpenGL can only render triangles. So the 256 triangles in Bryce probably just tell you how many polygons were used for the OpenGL preview.

If you render the ball as a polygon object with 256 triangles in Bryce you will probably get the same results as in Cheetah3D.

Bye,
Martin
 
Cinema 4d also has these "perfect spheres", but as Martin says, they only work as long as they stay just spheres.

Kali - it depends on the modeller, but some are able to reconnect split objects where the points share the same coordinates. Also, if there is some symmetry to your model, you could always export a half or quarter and then you friend could mirror it. I should think that most modellers will be able to open .obj though anyway.
 
Hi Martin.
Didn´t know this yet. Just wondering.
I have of course no idea of how Bryce is counting its polygons. So when it comes to metaballs it´s simply "guessing", as you can see. Here are 6 grouped metaballs, each 256 polygons of weight and the result is just 1536. That´s really mysterious for me.
But there´s another thing different renderer can handle: subdivision just for rendering purpose.

Frank
 

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Frank, I think I can explain. (You probably already know a lot of this, so I apologize if it sounds patronising, I am just trying to be thorough :))
The 256 polygon spheres are really just like the control cage of a subdivision modifier in Cheetah. It's like you can create a polygon cube with 6 sides, add a subdivision modifier and end up with an almost perfect sphere. I guess that in Bryce it only counts the control cage polygons. This also explains why the metaball object only has 1536 polygons, because Bryce is only counting the faces of the spheres, not the final rendered shape. In fact, to be really precise, the spheres and metaball object have no faces at all, they are defined by a mathematical formula. The spheres you see are just polygon representations that openGL can display. It is similar to how CAD apps like Amapi, and spline "patch" based modellers work.

Hope this helps. :)

P.S It might be possible to write a script that would only enable subdivision for rendering. Perhaps something to toggle the all the subdivision modifier property tick boxes in a scene on and off. I don't know anything about scripting though, so you'll have to ask the experts! :)
 
Hi squareitround.
Thanks for that explanation. So if I load a lowpoly object into Bryce and tell it to smooth that thing, its the same like increasing the number in the subdivision modifier in Cheetah3d? Ok - nevertheless cool thingy.
Thanx again.
Frank
 
There are also some methods to intersect isoparameter surfaces directly. I guess that's what Bryce does.

Is there no realtime preview of the Metaballs in Bryce?


Bye,
Martin
 
Hi Martin.
No, just a "nano preview", a rendered stamp. Bryce is becoming a primitive modeller in 6.0. with rudimentary export function. So far it´s more "lego".
Frank
 
Hi squareitround.
Thanks for that explanation. So if I load a lowpoly object into Bryce and tell it to smooth that thing, its the same like increasing the number in the subdivision modifier in Cheetah3d? Ok - nevertheless cool thingy.
Thanx again.
Frank

Yes, although it probably really works the way Martin says. He knows more about than me! :) My explanation was more of a way to visualize what happens.

P.S Have you tried Lego Digital Designer?

P.P.S Apologies to Martin for wandering so far of topic! ;)
 
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