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Wrong FOV on iPad 4

October 6, 2014 - 6:16am #1

Vuforia SDK Version: Unity 3.0.9.2 -
Description with steps to reproduce:

We are building an augmented app, in which some real-world Objects (a city) are precicely overlayed by some virtual content. We recently upgraded to Vuforia 3.0.9.2. Now everything worked fine when running the App on Ipad air, however on Ipad 4 the virtual objects do not match up perfectly (the farer away from the center/the marker, the worse). It seems like the vuforia camera is using a wrong Field of View, so that everything gets "distorted".

It's kind of hard to see the effect without a detailed real-life Scene on which the augmented stuff is projected, however it can be seen by taking a mid-sized cardboard box, measure it and recreate it in Unity and place an Image-Marker on the front. Now in Ipad Air the virtual Cube should somehow cover the real box, where on ipad 4 it does not align properly. Unfortunately i do not have the real-world city right here, but i made a demo project as described above, and although it does not align perfectly and is just a very rough setup, you can see the difference Ipad air/Ipad 4. I don't have any other stuff in the scene, just the cube and the Vuforia Plugin. 

 

"Correct" Ipad Air:

 

"Bad" Ipad 4:

 

 

By downgrading to an older Unity Version and Vuforia 2.8 everything was back to normal again.

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Development OS (Mac OS X, Windows, Linux): Mac OSX -
Mobile OS and Version: IOS 7.1 -
Mobile Device Manufacturer and Model name: Ipad air/Ipad 4 -
Do the Vuforia Sample Applications show the same behavior?:

Wrong FOV on iPad 4

December 9, 2014 - 12:57am #8

Will close this due to lack of feedback.

If you need to update this, please create a new thread and post a link to this thread for reference.

 

Wrong FOV on iPad 4

October 10, 2014 - 11:59am #7

Could you share one or two screenshots showing the cube placed on the target in your Unity scene ?

Also, one thing not fully clear is the mismatch between the box size:

16cm, y: 26.2 cm, z: 25cm.

and the target size: 

7.5 * 19 cm

If you can attach an image showing the Unity scene and highlight the dimensions in the scene, this would help us reproduce the same setup

Wrong FOV on iPad 4

October 10, 2014 - 12:56am #6

- what are the image target size as specified in the XML dataset file

Copied from the xml: 75.01002 width, 189.980179 height. Representing a 7.5 * 19 cm big Real-World Marker.

- are you changing the target size at runtime via any script ?

No. No scripts at all, just imported Vuforia, the Marker-dataset and created the cube.

- are you attaching the semi-transparent cube as a child of the Image Target in the Scene via the Unity Editor ? does the cube size matches the parent Target exactly in the Scene view ?

No child, just in the root of the scene. the cube is bigger as the target (as you can see in my screenshots), but the position in scene view is perfectly "as it should be".

- have you changed any specific settings in the AR Camera object ?

Just enabled the Marker-Dataset on the camera, did not change anything else.

- what are the exact dimensions of the cube (or parallelepiped / box) ?

Dimensions: x: 16cm, y: 26.2 cm, z: 25cm.

- do you have any script that applies some transformations to the cube or to the Image Target ? if so, is it making any assumption on the Camera FOV ?

As described above, no scripts at all. I found this issue in a way more complex app by our company, and so i created this really simple demo app, which shows the same behaviour. When i create the same with the old version of Vuforia (2.8) everything is just fine. I am using IOS 7.1 on both devices.

Wrong FOV on iPad 4

October 7, 2014 - 4:18am #5

Ca you share the exact details on how to reproduce it, i.e.:

- what are the image target size as specified in the XML dataset file

- are you changing the target size at runtime via any script ?

- are you attaching the semi-transparent cube as a child of the Image Target in the Scene via the Unity Editor ? does the cube size matches the parent Target exactly in the Scene view ?

- have you changed any specific settings in the AR Camera object ?

- what are the exact dimensions of the cube (or parallelepiped / box) ?

- do you have any script that applies some transformations to the cube or to the Image Target ? if so, is it making any assumption on the Camera FOV ?

and any other relevant  information you can think of, as it would be of help.

 

Wrong FOV on iPad 4

October 7, 2014 - 2:30am #4

Yes, this happens in landscape mode - our application is clamped in landscape right. I am downloading the multitarget example right now, but i could imagine that you won't see it on the small cube of the example - the offset/distortion is best seen on objects far away from the marker/center. I'll try the sample and report what's happening as soon as i downloaded it.

 

EDIT:

 

Downloaded the Multi-Marker Sample, there seems to be no "distortion", at least i can't see any at this size of the cube. I also tried my sample App in Portrait mode, which results in the same distortion. In my Sample i just created a brand new Project, imported Vuforia and a single Image Target and created the semi-transparent cube wich the correct dimensions to match my real-world cube. Nothing else in the project, no settings changed, all default. In Vuforia 2.8 everything works fine.

If you have and ideas what to try, let me know.

Wrong FOV on iPad 4

October 6, 2014 - 12:15pm #3

Is this happening in Landscape mode ? (it appears so from the screenshot, unless you have cropped them,.... please confirm).

 

Wrong FOV on iPad 4

October 6, 2014 - 12:14pm #2

Thanks for reporting the issue. I just tried the Unity Multi Target Sample app on iPad 4 and iPad Air and there is no noticeable offset like the way you are seeing it. Can you download the multi target sample app and try it on your iPad4/iPad Air. Let us know how it goes.

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