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Problem: Unity only showing the back face only of my model
Hi I have a major problem on my project that I am stuck with and have a deadline of the 24 Nov fast approaching and wonder if anyone can help or has had this same problem of mine.
I have a model of a engine part of a motorbike in a .IGS file format, that renders completely fine in Cinema 4D, however when putting it into Unity it only show the back faces of the model.
I have tried changing the normals, aligning them in Cinema 4D and putting it back into Unity but there is no change.
Also when putting the IGS file into Cinema 4D it comes up with a list of IGS import options. Is there something that I need to select in that at all that I have missed?
I would be grateful for any help. thanks.
I use $$anonymous$$aya so I don't know how similar they are in respect to fixing your problem although I get those problems as well. In $$anonymous$$aya i can change the renderer of objects to be one sided so I only see the face of objects and that is a good start to see what Unity will see. And a BIG one (at least in $$anonymous$$aya) is to delete non-deformer history ( non-deformer so you don't delete any animation you may have) . I found that even though I was working with the "history" button off and no visible history is recorded, that $$anonymous$$aya still does keep things in memory - maybe for the purpose of Ctrl-z undo's. When I have FBX exports that come out funky in Unity that is the reason most of the time - I forgot to delete history. I also found that if I DON"T delete history and it still works in unity, that if I reimport the FBX into $$anonymous$$aya it's pretty broken as far as skinning on animated objects.
Answer by Orion 1 · Nov 09, 2010 at 09:29 AM
I'm quite sure that Unity only shows the front faces of your model. Which means you'll have to flip them in Cinema 4D (there should be some operation called flip normals or flip faces).
You can also try and get Unity to render both faces. You can do this by either writing your own shader (if you don't know how, you might wanna check out the node based shader editor.
Alternatively you can use one of the Unity shaders that already renders both sides (although they all don't do lighting).
Or.. you just go to one of the forum threads where this has been thoroughly discussed already and copy a shader from there.
Answer by Yoerick · Nov 09, 2010 at 01:01 PM
I had the exact same problem. I had a model that rendered perfectly in Cinema 4D but when I exported it to Unity it was invisible. After a while I figured out the model's normals were reversed. I also tried to align the normals and reverse them but that didn't solve it.
However, I found a solution. I hope it works for you too because this one is quite simple and then you shouldn't worry about shaders. What I did: I selected the polygons in my model and used the function "Triangulate". When I exported this triangulated model, everything worked perfectly.
Side note: I exported my models in the .FBX format, don't know if that has anything to do with it but you could try that.
Btw, you could turn on backface culling in Cinema 4D, this way Cinema 4D will make backfaces invisible, just like Unity and you don't get any unexpected results. To turn it on go to Display -> Backface Culling.
Answer by pardox · Nov 23, 2010 at 03:34 AM
Grettings from Mxico
1.- Open your model in cinema
2.- Select al poligons in your mesh
3.- In functions pull down use align normals and reverse if necesary. (negative is blue and not render in unity, positive is orange)
4.- save your model and try it in unity
5.- if some holes keep in your model back to cinema and triangulate the model (save a copy before this).
good luck!!
Answer by Will Poole · Nov 10, 2010 at 12:04 PM
Cheers for the feedback guys much appreciated. Being a complete newbie to Unity and Cinema 4D, by any chance is there a tool or shortcut in Cinema 4D that will make all the normals of an object face the same way even though there half of the normal are facing the right way and the other half facing the other way, because when you go to reverse the normals if reverse both lots, vice versa ?????
You can do this by selecting the polygons and the go to Function -> Align normals ;)
Answer by jscnet · Nov 05, 2011 at 10:34 PM
I have the same problem. I've removed the front polygon from a Cube object. The outer polygons (normals) are visible however the inside isn't. Is there a way to apply the normals to both sides of a poly?