<summary><strong>Q:</strong> How can I disable or enable labeling on an object at runtime?</summary>
<summary><strong>Q: How can I disable or enable labeling on an object at runtime?</strong></summary>
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<summary><strong>Q:</strong> How can I remove or add new labels to objects at runtime?</summary>
<summary><strong>Q: How can I remove or add new labels to objects at runtime?</strong></summary>
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This can be achieved through modifying the `labels` list of the `Labeling` component. The key is to call `RefreshLabeling` on the component after making any changes to the labels. Example:
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<summary><strong>Q:</strong> Is it possible to label only parts of an object or assign different labels to different parts of objects?</summary>
<summary><strong>Q: Is it possible to label only parts of an object or assign different labels to different parts of objects?</strong></summary>
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Labeling works on the GameObject level, so to achieve the scenarios described here, you will need to break down your main object into multiple GameObjects parented to the same root object, and add `Labeling` components to each of the inner objects, as shown below.
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<summary><strong>Q:</strong> When visible surfaces of two objects are fully aligned, the bounding boxes seem to blink in and out of existence from one frame to another. Why is that?</summary>
<summary><strong>Q: When visible surfaces of two objects are fully aligned, the bounding boxes seem to blink in and out of existence from one frame to another. Why is that?</strong></summary>
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This is due to a common graphics problem called *z-fighting*. This occurs when the shader can't decide which of the two surfaces to draw on top of the other, since they both have the exact same distance from the camera. To fix this, simply move one of the objects slightly so that the two problematic surfaces do not fully align.
## <aname="randomization">Randomization</a>
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<summary><strong>Q:</strong> How can I have multiple sets of prefabs in a foreground placement Randomizer, and on every Iteration select one from each set?
<summary><strong>Q: How can I have multiple sets of prefabs in a foreground placement Randomizer, and on every Iteration select one from each set?</strong>
</summary>
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<summary><strong>Q:</strong> How can I specify an exact number of objects to place using the sample foreground object placement Randomizer? </summary>
<summary><strong>Q: How can I specify an exact number of objects to place using the sample foreground object placement Randomizer?</strong></summary>
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The provided `ForegroundObjectPlacementRandomizer` uses Poisson Disk sampling to find randomly positioned points in the space denoted by the provided `Width` and `Height` values. The distance between the sampled points will be at equal to `Separation Distance`. The number of sampled points will be the maximum number of points in the given area that match these criteria.
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<summary><strong>Q:</strong> How can I avoid object overlap with the sample foreground object placement Randomizer?</summary>
<summary><strong>Q: How can I avoid object overlap with the sample foreground object placement Randomizer?</strong></summary>
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There are a number of ways for procedurally placing objects while avoiding any overlap between them, and most of these methods can be rather complex and need to place objects in a sequence. All the modifications to the objects (like scale, rotation, etc.) would also need to happen before the next object is placed, so that the state of the world is fully known before each placement.
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<summary><strong>Q:</strong> What if I don't want randomized object placement? Can I move my objects in a non-randomized predefined manner on each frame? </summary>
<summary><strong>Q: What if I don't want randomized object placement? Can I move my objects in a non-randomized predefined manner on each frame?</strong></summary>
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Even though we call them Randomizers, you can use a Randomizer to perform any task through-out the execution lifecycle of your Scenario. The power of the Randomizers comes from the lifecycle hooks that they have into the Iteration and the Scenario, making it easy to know and guarantee when and in which order in the life of your simulation each piece of code runs. These functions include:
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<summary><strong>Q:</strong> The objects instantiated using the sample foreground placement Randomizer are floating in the air. How can I use this Randomizer to place objects on a horizontal surface instead? </summary>
<summary><strong>Q: The objects instantiated using the sample foreground placement Randomizer are floating in the air. How can I use this Randomizer to place objects on a horizontal surface instead?</strong></summary>
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The objects instantiated by the sample foreground Randomizer are all parented to an object named `Foreground Objects` at the root of the Scene Hierarchy. To modify the orientation of the objects, you can simply rotate this parent object at the beginning of the Scenario.
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<summary><strong>Q:</strong> Does using the same `Random Seed` value in two runs of the same Scenario guarantee that the generated datasets are identical?</summary>
<summary><strong>Q: Does using the same `Random Seed` value in two runs of the same Scenario guarantee that the generated datasets are identical?</strong></summary>
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If you only use the Samplers (and Parameters, which internally use Samplers) provided in the Perception package to generate random values throughout the Scenario's lifecycle and keep the `Random Seed` value unchanged, an identical sequence of random numbers will be generated every time the Scenario is run. This is because the Samplers obtain their seeds through continually mutating the provided global `Random Seed` in the Scenario.
<summary><strong>Q:</strong> What is the relationship between the Scenario's lifecycle properties (Iterations and Frames per Iteration) in conjunction with the Perception Camera's timing properties (Simulation Delta Time, Start at Frame, and Frames Between Captures). </summary>
<summary><strong>Q: What is the relationship between the Scenario's lifecycle properties (Iterations and Frames per Iteration) in conjunction with the Perception Camera's timing properties (Simulation Delta Time, Start at Frame, and Frames Between Captures). </summary>
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Each Iteration of the Scenario resets the Perception Camera's timing variables. Thus, you can think of each Iteration of the Scenario as one separate Perception Camera sequence, in which the camera's internal timing properties come into play. For instance, if you have 10 `Frames Per Iteration` on your Scenario, and your Perception Camera's `Start at Frame` value is set to 8, you will get two captures from the camera at the 9th and 10th frames of each Iteration (note that `Start at Frame` starts from 0). Similarly, you can use the `Frames Between Captures` to introduce intervals between captures. A value of 0 leads to all frames being captured.
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<summary><strong>Q:</strong> I want to simulate physics (or other accumulative behaviors such as auto-exposure) for a number of frames and let things settle before capturing the Scene. Is this possible with the Perception package?</summary>
<summary><strong>Q: I want to simulate physics (or other accumulative behaviors such as auto-exposure) for a number of frames and let things settle before capturing the Scene. Is this possible with the Perception package?</summary>
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The Perception Camera can be set to capture at specific frame intervals, rather than every frame. The `Frames Between Captures` value is set to 0 by default, which causes the camera to capture all frames; however, you can change this to 1 to capture every other frame, or larger numbers to allow more time between captures. You can also have the camera start capturing at a certain frame rather the first frame, by setting the `Start at Frame` value to a value other than 0. All of this timing happens within each Iteration of the Scenario, and gets reset when you advance to the next Iteration. Therefore, the combination of these properties and the Scenario's `Frames Per Iteration` property allows you to randomize the state of your Scene at the start of each Iteration, let things run for a number of frames, and then capture the Scene at the end of the Iteration.
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<summary><strong>Q:</strong> I do not want to use the Perception Camera to control the timing of my simulation or capture on a scheduled basis. Can I have a Perception Camera in my Scene and trigger captures manually from other scripts?</summary>
<summary><strong>Q: I do not want to use the Perception Camera to control the timing of my simulation or capture on a scheduled basis. Can I have a Perception Camera in my Scene and trigger captures manually from other scripts?</strong></summary>
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Yes. The Perception Camera offers two trigger modes, `Scheduled` and `Manual`, and these can be chosen in the editor UI for the camera. If you select the `Manual` mode, you will be able to trigger captures by calling the `RequestCapture()` method of `PerceptionCamera`. In this mode, you still have an option to dictate your simulation delta time with this camera, in order to have deterministic simulation progress between rendered frames. This is controlled using the `Affect Simulation Timing` checkbox.
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<summary><strong>Q:</strong> Can I have multiple Perception Cameras active in my Scene simultaneously?</summary>
<summary><strong>Q: Can I have multiple Perception Cameras active in my Scene simultaneously?</strong></summary>
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We currently do not support multiple active Perception Cameras, but you may be able to get things working partially if you clone the repository and modify parts of the code to fix some of the more easy-to-fix issues such as file sharing errors. You would also need to use render textures on all cameras. That said, there are still issues with the render pipeline that may prevent you from using Labelers of the same kind with different Label Configs on these cameras.
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<summary><strong>Q:</strong> My RGB images look darker than what I see in Unity Editor, when I render the Perception Camera to a texture. How can I fix this?
<summary><strong>Q: My RGB images look darker than what I see in Unity Editor, when I render the Perception Camera to a texture. How can I fix this?</strong>
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<summary><strong>Q:</strong> How do I report additional custom information in my output dataset for each frame or the whole simulation (e.g. 3D position of objects at the start of each Iteration, intensity of lights, etc.)?
<summary><strong>Q: How do I report additional custom information in my output dataset for each frame or the whole simulation (e.g. 3D position of objects at the start of each Iteration, intensity of lights, etc.)?</strong>
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## <aname="miscellaneous">Miscellaneous</a>
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<summary><strong>Q:</strong> Objects in my captured images have jagged edges, how can I fix this?
<summary><strong>Q: Objects in my captured images have jagged edges, how can I fix this?</strong>
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<summary><strong>Q:</strong> I am using an HDRP Unity project with Perception and my images have significant blurring around most objects. How can I remove this blur?
<summary><strong>Q: I am using an HDRP Unity project with Perception and my images have significant blurring around most objects. How can I remove this blur?</strong>
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<summary><strong>Q:</strong> Are all post processing effects provided by Unity safe to use?
<summary><strong>Q: Are all post processing effects provided by Unity safe to use?</strong>
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<summary><strong>Q:</strong> What post processing effects can help improve model performance?
<summary><strong>Q: What post processing effects can help improve model performance?</strong>
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<summary><strong>Q:</strong> Can I debug my C# code?
<summary><strong>Q: Can I debug my C# code?
</summary>
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<summary><strong>Q:</strong> What kind of synthetic environment will be best for my use-case?
<summary><strong>Q: What kind of synthetic environment will be best for my use-case?</strong>
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<summary><strong>Q:</strong> Can I have more realistic rendering in my Scene?
<summary><strong>Q: Can I have more realistic rendering in my Scene?</strong>
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<summary><strong>Q:</strong> I am randomizing my Scene every frame and using ray casting to detect the position of objects, but my ray casts are returning incorrect results. What is the issue here?
<summary><strong>Q: I am randomizing my Scene every frame and using ray casting to detect the position of objects, but my ray casts are returning incorrect results. What is the issue here?
Mohsen Kamalzadeh
3 年前