PNG sequence filename tips

2025-03-06 10:14 UTC gpt-4o Open in ChatGPT ↗

In TouchDesigner, when saving a PNG sequence, you should include a frame number padding in the filename to prevent overwriting.

Recommended Filename Format:

image_name_####.png

image_name_$F4.png

Explanation:

#### (or $F4): Represents a 4-digit frame number (e.g., 0001, 0002, 0003…).
This ensures each frame gets a unique filename, preventing overwriting.

Variations Based on Frame Padding:

$F → No padding (1, 2, 3, … 10, 11)
$F2 → 2-digit padding (01, 02, … 99)
$F3 → 3-digit padding (001, 002, … 999)
$F4 → 4-digit padding (0001, 0002, … 9999) (Most common for consistency)

Example Output Filenames:

render_0001.png
render_0002.png
render_0003.png
...

Using $F4 avoids overwriting and ensures TouchDesigner correctly orders your sequence.

Let me know if you need further clarification! 🚀

If TouchDesigner is giving you an “invalid filename” error when using $F, you can try explicitly formatting the filename using Python expressions or manual padding.

Alternative Solutions:

1. Use Python Expression in the Filename Field

Instead of $F, use:

image_name_{:04d}.png

This ensures four-digit padding, like image_name_0001.png, image_name_0002.png, etc.

2. Use the Built-in Frame Number Variable Correctly

Try:

image_name_$F4.png

image_name_$F03.png  # 3-digit padding
image_name_$F02.png  # 2-digit padding

3. Use an Absolute Filepath

If the issue persists, ensure you are specifying a full path:

C:/my_renders/image_name_$F4.png

4. Check Your Output File Settings

If using a Movie File Out TOP, ensure the “File Type” is set to “Image Sequence (.png)”.
If using a Save Image Parameter, verify the file extension (.png) is correct.

Let me know if you’re still facing issues! 🚀

If TouchDesigner is giving an “Invalid Filename” error when trying to save a PNG sequence, here are the correct steps to ensure your filename format works properly:

Correct Filename Format for PNG Sequences

Instead of $F (which sometimes doesn’t work in file paths), use frame number formatting specific to TouchDesigner:

1. Correct File Naming Format

Use:

image_name.`frame`.png

image_name.####.png

🔹 Explanation:

#### is a placeholder that will be automatically replaced by the frame number (e.g., image_name.0001.png).
The dot (.) before the frame number is required in some cases.

2. Correct Setup in TouchDesigner

If you’re using a Movie File Out TOP:

Set “File Type” → “Image Sequence (.png)”
In “Filename” field, enter:
```
C:/my_renders/image_name.####.png
```
Frame Padding: Adjust padding under Movie File Out TOP settings.

3. Alternative Python Expression (If Needed)

If you need a more manual approach (e.g., scripting):

op('moviefileout1').par.file = "C:/my_renders/image_name.{:04d}.png".format(int(me.time.frame))

🔹 This ensures filenames like:

image_name.0001.png
image_name.0002.png

4. Debugging Steps

If you still get an “Invalid Filename” error: ✅ Check Your Save Location: Avoid saving to system-protected folders (e.g., C:/Program Files).
✅ Ensure the Movie File Out TOP is Active: Start rendering before checking file output.
✅ Try Using an Absolute Path: Specify the full save location.

Example Output Filenames (Using `####` Format)

C:/my_renders/image_name.0001.png
C:/my_renders/image_name.0002.png
C:/my_renders/image_name.0003.png
...

This should prevent overwriting and work smoothly in TouchDesigner. Let me know if you need more help! 🚀