# IrisVirtual
*IrisVirtual* is a feature allowing you to estimate the number of cameras your project might need, together with their location, orientation and lens type.
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IrisVirtual is under development, so the features and capabilities will likely change in the upcoming releases.
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## The process
1. Add as many Iris cameras into your viewport as you think you will need and place them as you think appropriate
2. Map the projection objects to these cameras
3. Run IrisVirtual which will tell you if your setup is likely to work.
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Your projection object(s) need to be properly UV mapped in order for IrisVirtual to work.
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Say, you want to perform a projection mapping on a cave-like projection mapping setup as shown below:
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Please make sure the resolution of your projection object is sufficiently high. As a rule, the individual pixel of the projection object should be the same or smaller size than the projected pixel. The latter depends on the resolution of the projectors and their distance and FOV from the projection object.
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In the above setup, there are 8 projectors. With IrisVirtual you will be able to get an understanding of how many cameras you should need, which lenses you should choose and where you would need to place them
So to evaluate your planned setup, place Iris cameras in the Viewport and choose the lenses you want to run the evaluation for.
Then, open **Iris** window and select the **Iris camera(s)** and all 8 projectors.
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Make sure **IrisVirtual** checkbox is selected
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When you hit **Calibrate** button, the process will start
If the result is successful, the ***Reprojection errors*** for all of the selected projectors will be below 0.
## Interpreting IrisVirtual results
IrisVirtual returns either a positive or a negative result and there are some caveats when interpreting them.
### **Negative IrisVirtual Results**
IrisVirtual can return 2 types of negative results: either reprojection error is above 1 px or the result says *“Insufficient number of points”.*
The causes can be different:
1. The camera does not see the entire projected area of the object
2. The area projected by any one projector is too small when viewed by the camera
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**Good to know:** if in doubt, feel free to contact us and send us your project so that we can have a look at it.
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### Positive IrisVirtual Result
Positive result means that your Iris setup should work, however please see below:
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There are cases when IrisVirtual returns a positive result (reprojection error below 1 px for all projectors) but in reality the setup most likely wouldn't work.
Before making a final decision, please send us your project file so that we can re-evaluate your planned Iris setup.
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