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Problems with Multiple Virtual Buttons

August 13, 2012 - 2:07pm #1

We are experiencing various issues with virtual buttons.

 

The symptoms are one or more of the following:

Buttons not recognized

Buttons are automatically activated upon launch of the App

Buttons seem to toggle on and off

Buttons on multiple button builds, toggle between themselves randomly.

 

We have worked on our marker and made sure that the image areas of the button have plenty of detail. Should we try to make a marker of that that local area and test its readability? Or is the whole marker the key and the marker area is only a measured region of the whole and the image in that area is not that importnat.

Is there any issues related to the distance the camera is away from the marker in Unity? If so, is there any rules to apply here?

Is there dependancy on marker size? Scene size in Unity?

Does scaling the marker or the scene have any bearing on this in unity?

Is it better to use a set scale between Unity/Marker and Real World unit? Such as, use a 1 Unity unit to 1mm. If this is the case, what overall size does Vuforia like, in the Unity environment?  Lets say our scene is 1000 units. Should our marker be 1000?  Should the camera be 1000 units from the marker?

Does a printed marker real world measurement have any influence? Should it be realated to this scale? So if I continue with my example of a marker being 1000 units, should I pring the marker to be a meter wide? what hapens if our graphics go out of this area?

Does the number of pixels of the marker play any factor?

We would very much like to have the ability to have multiple virtual buttons, but we can not get a stable build. 

Any advice would be extremely helpful as wel have client demos all this week.

Feel free to PM me.

Thanks

Eric

 

Problems with Multiple Virtual Buttons

August 13, 2012 - 7:55pm #5

Thanks so much for all your detailed answers. I will look into all your suggestions and report back to the group.

Problems with Multiple Virtual Buttons

August 13, 2012 - 7:39pm #4

The symptoms are one or more of the following:

Buttons not recognized

See Vincekilians comments on the minimum recommended VB area (1/10th of the target area) and target scaling. Also ensure that your VB's each have a unique name.

Buttons are automatically activated upon launch of the App

Are all of your VBs children of an ImageTarget?

Buttons seem to toggle on and off

Are you seeing log messages indicating this, or unexpected behavior in your scene?

Buttons on multiple button builds, toggle between themselves randomly.

Again, make sure that they have unique names, and they shouldn't overlap.

How many VBs are you using?

We have worked on our marker and made sure that the image areas of the button have plenty of detail. Should we try to make a marker of that that local area and test its readability? Or is the whole marker the key and the marker area is only a measured region of the whole and the image in that area is not that importnat.

You can determine the suitability of a target region by analyzing the grayscale version of your image in the TMS. The yellow hatches on the image mark the descriptors, which describe the features of the target. Look for regions with a good density and distribution of descriptors. The VB is activated when the features within its border are occluded.

Is there any issues related to the distance the camera is away from the marker in Unity? If so, is there any rules to apply here?

No the position and orientation of the camera in the Unity scene only affects its perspective in Play Mode.

Is there dependancy on marker size? Scene size in Unity?

The target's width value, which you provide to the TMS, defines the unit scale for the scene.

Does scaling the marker or the scene have any bearing on this in unity?

Not when scaling the ImageTarget in the Editor, but it does if your revise the Trackable's width and height in the DataSet's XML file. Be sure to maintain the aspect ratio if you do this.

Is it better to use a set scale between Unity/Marker and Real World unit? Such as, use a 1 Unity unit to 1mm. If this is the case, what overall size does Vuforia like, in the Unity environment?  Lets say our scene is 1000 units. Should our marker be 1000?  Should the camera be 1000 units from the marker?

There is no dependency on the real world scale. Though matching this can be useful for applications where the virtual and real unit scales should coincide for performing measurements, etc..

It's recommended that the minimum and maximum dimensions fall within the clipping plane distances of the camera, which default to 10 and 1000. But this isn't a strict rule. Where you will typically see problems, is when the dimensions are too small and fall below the depth of the near clipping plane.

Does a printed marker real world measurement have any influence? Should it be realated to this scale? So if I continue with my example of a marker being 1000 units, should I pring the marker to be a meter wide? what hapens if our graphics go out of this area?

The augmentation will be scaled proportionally to the size of the physical target. So long as the details are apparent, it will be trackable.  Rendered elements that extend past the border of the target, or above the target, will be posed less precisely. This eventually results in a noticeable 'jitter' as you increase the distance from the target's center. The distance at which the jitter becomes apparent is a factor of the quality of the target, which relates to the density and distribution of trackable features.

Does the number of pixels of the marker play any factor?

No. The unit scale is arbitrary - you're defining it yourself.

We would very much like to have the ability to have multiple virtual buttons, but we can not get a stable build. 

Any advice would be extremely helpful as wel have client demos all this week.

It will be helpful if you can send me a screen grab of your expanded project hierarchy and scene view.

Problems with Multiple Virtual Buttons

August 13, 2012 - 7:12pm #3

Thanks very much Vince. 

Did I miss the suggestion of the 10% of the trackable scale in the documentation somewhere?  Maybe there is more I missed. Can you please send me a link to that statement, if you remember where you saw it?

When you are referring to real world scale, is there a maximum I should be looking at. If the units are 1mm, then is 1-2 meters appropriate for a scene size? Or 2000 units? 

Anyone know of how the scale of the marker width comes into play?  It must be there for a reason. Should I set it to the width of the whole scenes graphics? Or to the size I have the marker scalled to in Unity units?

Thanks again, looking forward to more replys.

 

 

Problems with Multiple Virtual Buttons

August 13, 2012 - 2:21pm #2

Best practice states that your virtual buttons should be no less than 10% of your total trackable's scale.

Naturally, the further back you are from your trackable image, the smaller your buttons become - this would mean that the further back you are the more issues you could run into (set the far clip plane to a lower value to prevent distances greater than your preset threshold.)

Marker size shouldn't matter, nor should scene size in Unity (unless of course your scene is unnecessarily massive which would cause problems no matter what on mobile devices).

As for scale, Unity tends to prefer that you work at a real-world scale.  I have seen many, many issues that are solved simply by working at true scale (if you're unsure, just create a new Cube primitive in your scene - it will default to 1m x 1m x 1m in size.)  Now you can scale your gameobjects according to the reference cube.

We have used multiple virtual buttons on multiple trackables in a single scene without issues.

If possible, post a link to a sample project.  With this many questions in a single post its tough to cover all the bases without seeing what's going on under the hood.

Feel free to PM the link if you're concerned with privacy.

Vince

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