Update README.md

scripts/rendering/README.md

@@ -39,11 +39,55 @@ cd ../.. && \
 
 ## 📸 Example Usage
 
-After setup, you can render objects using the `main.py` script:
+After setup, we can start to render objects using the `main.py` script:
 
 ```bash
 python3 main.py
 ```
 
-USDZ support is experimental. Since Blender does not natively support usdz, we use [this Blender addon](https://github.com/robmcrosby/BlenderUSDZ), but it doesn't work with all types of USDZs. If you have a better solution, PRs are very much welcome 😄!
+After running this, you should see 10 zip files located in `~/.objaverse/github/renders`, which correspond to renders of objects from [our example 3D objects repo](https://github.com/mattdeitke/objaverse-xl-test-files):
+
+```bash
+> ls ~/.objaverse/github/renders
+0fde27a0-99f0-5029-8e20-be9b8ecabb59.zip  54f7478b-4983-5541-8cf7-1ab2e39a842e.zip  93499b75-3ee0-5069-8f4b-1bab60d2e6d6.zip
+21dd4d7b-b203-5d00-b325-0c041f43524e.zip  5babbc61-d4e1-5b5c-9b47-44994bbf958e.zip  ab30e24f-1046-5257-8806-2e346f4efebe.zip
+415ca2d5-9d87-568c-a5ff-73048a084229.zip  5f6d2547-3661-54d5-9895-bebc342c753d.zip
+44414a2a-e8f0-5a5f-bb58-6be50d8fd034.zip  8a170083-0529-547f-90ec-ebc32eafe594.zip
+```
+
+If we unzip one of the zip files:
+
+```bash
+> cd ~/.objaverse/github/renders
+> unzip 0fde27a0-99f0-5029-8e20-be9b8ecabb59.zip
+```
+
+we will see that there is a new `0fde27a0-99f0-5029-8e20-be9b8ecabb59` directory. If we look in that directory, we'll find the following files:
+
+```bash
+> ls 0fde27a0-99f0-5029-8e20-be9b8ecabb59
+000.npy  001.npy  002.npy  003.npy  004.npy  005.npy  006.npy  007.npy  008.npy  009.npy  010.npy  011.npy  metadata.json
+000.png  001.png  002.png  003.png  004.png  005.png  006.png  007.png  008.png  009.png  010.png  011.png
+```
+
+Here, we see that there are 12 renders `[000-011].png`. Each render will look something like one of the 4 images shown below, but likely with the camera at a different location as its location is randomized during rendering:
+
+![temp](https://github.com/allenai/objaverse-xl/assets/28768645/69d79e26-4df1-4bd2-854c-7d3c888adae7)
+
+Additionally, there are 12 npy files `[000-011].npy`, which information about the cameras pose for a given render. We can read the npy files using:
+
+```python
+import numpy as np
+array = np.load("000.npy")
+```
+
+where array is now a 3x4 [camera matrix](https://en.wikipedia.org/wiki/Camera_matrix) that looks something like:
+
+```python
+array([[6.07966840e-01,  7.93962419e-01,  3.18103019e-08,  2.10451518e-07],
+       [4.75670159e-01, -3.64238620e-01,  8.00667346e-01, -5.96046448e-08],
+       [6.35699809e-01, -4.86779213e-01, -5.99109232e-01, -1.66008198e+00]])
+```
+
+**Note.** USDZ support is experimental. Since Blender does not natively support usdz, we use [this Blender addon](https://github.com/robmcrosby/BlenderUSDZ), but it doesn't work with all types of USDZs. If you have a better solution, PRs are very much welcome 😄!