what is the recommended way, in three js, to render (mostly) static scene - three.js

Question

I have a scene that is mostly static, i.e. without user interaction it doesn't change (animations).
The user interacts with the scene. For example:
when the user clicks on certain location in a map, another image opens in another pane
the user may move the camera by moving the mouse
etc...
Originally I implemented the rendering via animate(), which calls:
function animate() {
requestAnimationFrame( animate );
render();
controls.update();
}
This works fine (in terms of response) except that
the rendering happens constantly, which is not necessary.
for one of the admin pages, which does not show the scene, I'm getting runtime errors when the scene does not exist, but the rendering still goes on...
So I re-implemented the rendering by calling, explicitly, after user action which change the scene
render();
controls.update();
This requires more work, because I have to cover all the cases where the scene changes.
In one of the cases, the behaviour is not as expected (the rendered scene is black and explicit call to render does not fix the problem).
The link here says that if your scene is static, there is no reason for an animation loop.
The link here suggests to use animate().
My questions:
Is explicit render, a good pattern to use in three js for static scenes?
Are there pros to render only when needed, instead of calling animate which renders constantly, when this is not needed?
In terms of resource load in general

Answer 1

The link here says that if your scene is static, there is no reason for an animation loop.
The answer of the respective stackoverflow question is also the correct one. The second link is unrelated to question whether to use on-demand rendering or not.
In general, having an animation loop requires more resources since you constantly render no matter if the scene changes or not. However, certain application like 3D viewers (without animation playback) do not need to do this. It's sufficient to render only when certain events happen (e.g. user interaction).
Is explicit render, a good pattern to use in three js for static scenes?
Yes, it is. It is a good pattern for 3D applications in general.
Are there pros to render only when needed, instead of calling animate which renders constantly, when this is not needed? In terms of resource load in general
The app requires less resources which is always a good thing. E.g. mobile device will save a lot of battery and laptops or desktops will be more quiet.