Is there a way to get Anti-Alias for the Curve Brush Engine?

The engine was deliberately created that way. If there is a will to implement the feature request you created for the same topic, Anti-Alias for Curve Brush engine?, I don’t know, it may be possible, but I don’t think it will happen.

What you could do is creating things with this engine on a separate layer and then use G’MIC on it. To start it do Filter > Start G'MIC-Qt and then you have a few options under:
Repair

  • Anti Alias
  • Smooth [Antialias]
  • Unquantize [JPEG Smooth]

as well as under:
Testing

  • Lylejk
    → Lylejk Quantize Wicker
  • Samj
    → Details
    → → Antialias Wavelet

But you have to find out yourself which works best for you.

Michelist