Have any of you experienced geometry transfer problems from Cheetah3D to Unity? What might be the reason for the mesh exploding if there are no bones in the models?
The geometry is originally from 3DS MAX, but Cheetah3D shows it just fine and additions are made in Cheetah3D to the original model. The .jas was saved to Unity Pro project folder. See the result image attached.
After discussing this with Martin, it seems that the problem is Unity related as other 3D software (Maya, MAX, Cinema4D) load the scene via path Cheetah3D → FBX → 3D App just fine. Unity is the only one that explodes the meshes.
Thats one of those report bug type scenarios that means the brains round here gets to see your model and work out what caused it to go astray. It some times happens to me from bryce to unity or bryce>maya>Unity, if I make something with loads of intense angles and long n-gons. Try saving it to a few different formats though, that might fix it?
Good luck, it looks like a sweet model.
AC
I’ve occasionally had problems with models from Blender importing wrong if they are saved with quads. If I convert the quads to triangles, the problem goes away. No idea if that’s the case here, but I’d thought I’d mention it.
–Eric
I never had any issues with static mesh export from C4D. If you like, i will give it a try, exporting the model from c4d to fbx. C4d can read .3ds files, so this wont be a problem, i think.
Edit:
Maybe there is a problem with n-gon export? Did you use any n-gons in the original model?
Try unchecking recalculate normals inside of the Unity import settings of the model.
-Jon
Thank you for your responses. Actually some of these misbehaving objects are from our client that wants us to prepare a visualization from a set of models that we got in FBX format. According to your suggestions I’ve tried so far:
There are no bones and shouldn’t have ngons in the model (esp. after triangulate in Cheetah).
None of this helps. The worst thing is that we do have several of these models coming to us that we can’t get into Unity in a proper way, while they seem to be ok in Cheetah3D, Maya and according to Martin at least in one test case in C4D also.
The whole scene is fairly large, but I can e-mail one exploding object (telescope) to Alpha-loop, thanks for the offer of having a look at this! See the images attached how the telescope model behaves in Cheetah and in Unity PRO in this post.
We’d like to be able to show something working to our client soon. I’ll also send the telescope object via the bug report tool to the Unity guys, any help greatly appreciated!
Ok, maybe this will help.
If you have “impossible Quads” in your Model, the triangulation could mess up the model, like shown in this example…
Until triangulation your model may look fine inside the 3D app.
If your model contains some of these, try to triangulate the quads by hand, before giving the rest to the software. In some apps you can also flip the verts, that part the quad. Could be worth a try!
Cant think of another solution yet. And i am still willing to test one or part of your model from C4D converted to FBX to Unity, if you want that.
Cya
Frank
It might help if you posted the model, so we can take a look at it.
I posted the telescope scene with the reporting tool as Case 10466. Do you need some other form of posting? I also sent the FBX via e-mail to Alpha-Loop, even this part seems to be 4M zipped so it may get stuck somewhere in between.
Thanks,
4 Mbs are no problem. I will give it a try!
That looks like a Lot of polygons. are you sure it isn’t a vertex count problem?
Hmm. Maybe in Maya, have the polycount HUD visible and select the model>merge verticies?-Maybe the model is built a bit funny? And yes, triangulating it in Maya is a good idea too.
Post the models here, if someone can get them working, we can send them to you in a unitypackage?
AC
Hope the forum does not get stuck with this… It is the original fbx that I received, zipped. Hmm, regarding the polygon count: if there are too many polygons, would it still load? I’ve experienced polygon count complaints in Unit with other models from the clients, but then the whole model didn’t appear at all when dragged to the scene.
If this is related to the polygon count, it is a bit problematic as in product model visualization the models can be originally from CAD. Those programs tend to triangulate their parametric surfaces to a huge soup of triangles. Naturally there is no sense in displaying 1000 000 tri coffee cup, but it might be fairly difficult to reduce the triangle count to 1000 for example without the model breaking up in the reduction tool already. As far as I understand some reduction has already being done for the telescope (I do not know if this was originally a CAD model), but this model can tolerate more reduction I think.
It is very interesting to us to see how this turns out as I’m afraid we can sometimes get quite big models from clients. However I have to say that I got approx 400 000 tri machine model yesterday from a client’s SolidWorks CAD program and it displayed in Unity just fine after getting it to FBX! The reason for this was that no single part had more than 40k tris.
I have to check the Maya hints as well mentioned here.
Thanks again for assistance!
-JR
33915–1231–$skooppifbx_786.zip (3.96 MB)
Hmm… is this some kind of 3D Scan or was polygon reduction used on it?
There are many parts with very unclean geometry.
The dish for example will have shading issues in the areas marked 1 and 2. A round form should be modeled with polys of equal size, or as equal as you can make them. The geometry piercing through the dish at point 3 will also cause flickering or even worse effects.
The Triangulation is really messed up. To guarantee a clean shading and geometry rendering the triangulation should follow an equal pattern. This is not given in any way throughout the complete model. The tris are very long, normally two “good” tris should form something equal to a quad or rectangle.
Automatic optimization function of C4d removed more than 4.000 Polygons, that shared the same space, or of geometry with a thickness of 0. That will lead to display problems too.
There are normals flipped, wich will cause rendering issues.
I could continue the list on and on… in one word the model is a complete mess, in my opinion unusable and non-fixable at this state. I can tell only one thing for sure here… your problem is not unity or max related, it lies in the model itself.
Is there an untriangulated version i can look at? At best a model, that was not send through poly-reduction processes as well… Parts of the original Model will be enough to evaluate the original quality and to find a solution. 3DS Format is no problem.
Thanks for having look at the model. Sure it is not a nicely constructed model. However this is the stuff we got. And this is not the first time things are like this.
In the gaming world people can build models nicely for a specific purpose. In the product visualization world the situation can be a little tricky: we are sometimes forced to try to cope with models coming from CAD packages like CATIA, SolidWorks and others and there may not be enough resources to remodel the meshes from scratch. The meshes tend to be sometimes nearly very difficult to use for nice visualization.
However with this particular example: I still don’t understand why Cheetah, C4D and other display it correctly (in its not so nice state) and Unity just explodes it?
Sorry I didn’t answer to the question if I have non-triangulated model. The FBX is what I’ve got, but I’ll try to ask for a model in its more original form!
I dont really know the exact reason, but a game engine is optimized for speed and realtime effects and therefore needs optimized input as well to do a good job. Living within boundaries is what GameDev is about… Thats for sure.
And just to mention, putting shaders on that model for high quality renderings would surely end up with light- and renderartefacts, when taking a closer look.
But i see your problem. And its not a small one if your client has no other files…
When you get other data than the posted .fbx, feel free to send them in anytime and i ll take a look.
Frank
I’ve been following this thread as we are also frequently called upon to work with models that originated in Solidworks or some other NURBS CAD system. Like yourself, the models we often get are in the hundreds of thousands of poly’s in size. The problem is that no current game engine (that I know of at least) is designed to handle such large numbers of poly’s (EDIT: And as Alpha Loup correctly explained, game engines also require specific mesh qualities in order to properly display a 3D model) and the CAD apps themselves usually don’t do a very good job of optimizing their output. Even the 3D tools we normally use to produce our models (Cinema 4D, Carrara Pro, Modo and Blender) don’t seem to handle such huge poly models very well. (Side note: Beleive it or not, Blender seems to handle high poly models the best of everything I’ve tried so far.)
The only reliable and economical solution we’ve found so far is to manually re-create the entire model to bring its poly count to a manageable level. Optimum poly counts for Unity are around 4,000 per object, and that’s normally what we shoot for.
The other option is to use one of the mesh reduction applications available, but the only one that IMHO does a decent job of maintaining the mesh’s geometry while bringing the polycount down to a usable size is way out of our price range (SIMS Rational Reducer sim.no ).
Hope this helps.
I can second and recommend that. But looking at the complexity of the models it will sure take about 2 - 3 weeks per model time and a pro skilled vertex-pusher 
who knows what he is doing… when you aint got that at hand, its getting something between expensive and impossible.
But hopefully there will be cleaned up models available. C4D for example comes with a very easy to use poly-reduction tool. And as long as the original is made of clean quads and is then triangulated, it comes out with good and fast results. I will give it a try, when i get the new test model.