Rendering preview during drag slider phase

When dragging sliders of river device, preview is already generated during drag phase, not after drop. Which makes dragging almost impossible.

Change the Speed|Quality slider, maybe this helps? A high quality + high final resolution can give way to stuttering UI.

Thanks, but this is just workaround. WM isnt realtime anyway…Slider shouldnt update during drag phase, this is bug :slight_smile:

I think it should! It is really helpful if the slider of, for example the Select Height device, updates with every move.

You may be able to reduce your “preview base resolution” to 64px gain acceptable performance in preferences.

The river device is slow to generate its geometry, but fast to evaluate. This means it has a high “fixed cost” no matter what preview resolution is used, making it somewhat problematic for the real-time preview.

I very much want as many editing operations to be at a high quality with interactive framerates. It’s much easier to make precise edits with the minimum amount of tweaking when that is the case. However, I hear you - river is currently too slow for that to be effective.

The short term fix I can implement for this is, if WM is unable to maintain your desired performance target even at the base preview resolution, it should stop conducting an interactive preview altogether. The system will keep track of this on a per-device basis the same way it adaptively manages the preview res, so that just the river device “drops out” when performance is too low.

Long term, there will be some improvements coming down the pipeline for the River device, but they’re a ways out yet, so the short term fix is the solution for the immediate future.


Thanks for your reply and care. Interactive preview is mostly fine (for cheap devices, I am currently using 128px), but usualy when finetuning something, it is too low res to se any changes anyway, so quick build is the only way. I really like last versions, WM is really significantly faster, so even 100+ devices project builds in 4k in around 10 seconds, this is simply incredible.
Being not realtime is IMHO big advantage (in this case) of WM, because you can have very complex project. In compare to WC, even now it cant turn off realtime build of everything, so once you have just little bit more complex project, similar case literally kills UI and you cant do anything. So I was quite surprised, that this happend also here.

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“I think it should! It is really helpful if the slider of, for example the Select Height device, updates with every move.”

Ok, in this case I agree, my wrong.

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Respect for saying that out loud <3

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I’ve made three changes that should help this.

  1. The Layout/Edit view has a new toggle that lets you turn on/off interactive preview behavior.
  2. The minimum preview resolution is reduced to 32px if desired; this can help with extremely complex/slow previews.
  3. The River device now parallelizes the geometry generation of the rivers; This doesn’t make a single river any faster, but multiple rivers are built in parallel making tributary networks significantly faster.
  4. As a result of all of the above giving some ‘headroom’, the River device now previews vertex dragging as well, which is very helpful when trying to get things looking just like you want.

I experimented with having the preview drop out automatically but I found it led to a lot of edge cases that didn’t feel very fluid. Instead, you can simply toggle off interactive previews if working with a very complex/slow setup, while the other mitigations make normal river editing work fine.


Thanks Stephen, you are the best :slight_smile: