Rhino lens length to Unity


I need to export a rhino model to Unity 3D. I’m doing this as a fbx file. Along with that I need to send some camera view information to Unity. My question is about adding the lens length to Unity. Unity doesn’t have something called lens length, But there’s some thing called field of view. I would like to know how to convert the lens length to field of view (if they are related) or if there’s any other matching property in Unity.


Hi Madhu,

I can’t vouch for any of the results you’ll find being accurate but I ran a search for ‘converting lens length to field of view’ and found a bunch of online calculators that can probably help… I use the first one. I am not familiar with Unity though for any other suggestions there.

The result I found for the default 50mm camera in Rhino was 46.79 degrees but many of the calculators specify certain lens brands and I’m am unclear how that effects the result.

Thanks. I’ll have a look at them.

what are you up to in Unity?

I’ve done some experimentation with this to varying degrees of success.

In Unity we are building an App to show different 3D models for some training event. My client creates the 3D models in Rhino. So I’m importing them to Unity. One 3D model can have 3 camera views to show it in different angels. So the client is sharing these camera view details like below for example.
Using these values I’m setting the camera views in Unity. My problem is converting the focalLength(Lens length in Rhino) to Field of view value of Unity.
With the help of previous reply I found this http://paulbourke.net/miscellaneous/lens/
And I’m planning to use "vertical field of view = 2 atan(0.5 height / focal length)"
But now I’m having a issue of finding the value of height. Not sure what to use for that.


camName "Name View 1"
camGroup "Name View 1_Grp"
focalLen "49"
Cx "29.1070392477262"
Cy "32.2508470958018"
Cz "89.5861273886465"
Tx "0"
Ty "0"
Tz “0”

camName "Name View 2"
camGroup "Name View 2_Grp"
focalLen "49"
Cx "2.9038526478832"
Cy "99.2149465666948"
Cz "7.80852804487048"
Tx "0"
Ty "0"
Tz “0”

camName "Side View"
camGroup "Side View_Grp"
focalLen "49"
Cx "82.9710911032618"
Cy "31.0804895092999"
Cz "14.463142097058"
Tx "10.4951110723463"
Ty "0.999934019398793"
Tz “-4.14650803054286”

Did you ever work out a reliable equation to convert lens length? I’m trying to do the same now.
Is Lens length the same s focal length?
Seems to me that Focal length is not an absolute parameter to define field of view and ratio will vary from manufacturer.

@guido This is what I did. Hope this help.


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You should be able to just set the physical camera focal length in Unity directly… No conversion needed.



Did you try to import 3dm file with cameras to Blender than export to Unity?
I don’t know if it is possible from Blender to Unity