modal-example-animations.html

<button class="btn btn-primary" (click)="animateModal.show()">Modal With Animation</button>
<ng-template nzbModal #animateModal="nzbModal">
  <!-- NOTE .fade class -->
  <div class="modal fade" tabindex="-1">...</div>
</ng-template>

<button class="btn btn-primary" (click)="inanimateModal.show()">Modal Without Animation</button>
<ng-template nzbModal #inanimateModal="nzbModal">
  <!-- NOTE  absence of .fade class -->
  <div class="modal" tabindex="-1">...</div>
</ng-template>