RenderViewFamily ultra high but low DrawCalls

Development Rendering
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1

Hello,

RenderViewFamily is on slower test PC at 45ms, this is way too high.
InitViews 40ms
RenderQueryResult 39 ms.

When using stat gpu, I see basepass is ultra high. So I tested GPU SceneRendering, but draw calls seems not to be high. Also tried GPU Visualize (CTRL + Shift + ,), but it is not giving me a better guess of what is happening here and why.

Any idea how to get the reason behind this incredible high values?

321649-renderfamilyultrahigh.png
321649-renderfamilyultrahigh.png1226×646 820 KB

Thanks a lot!

2

Hello, MrFly:
I am also stuck in this, have u found a way to solve it?

3

Hi XIAOCHANGJIANG,
Sorry, but still no (real) solution. I took the screenshot from a slower machine (PC). Later on a bigger machine (PC) I did more analysis. In the end (I think) it turned out nav-mesh was the biggest factor which drove up GPU. By improving nav-mesh a lot (make it much smaller), also stats on slower machine became better.
I was wondering a lot that nav-mesh is able to higher GPU load such big at all.

How I analyzed?

  • I switched off groups of elements one by one to figure it out. I am still not sure what happened.
  • I still wondering, why the UE4 analysis tools are not really getting direct insights what exactly is ramping up render family (when draw calls are low).

Still open questions:

  • If someone here can explain how RenderViewFamily and Basepass can be so very, very high without showing high draw calls, I still want to know.
  • Also a good advice how to pin point fast what assets/settings in the game are causing the very, very high Render View Family and Basepass, would be great.
4

I also have a problem with that.

331258-screenshot-2021-03-02-083344.jpg
331258-screenshot-2021-03-02-083344.jpg1920×1080 823 KB

5

Yes, sorry, I also never got any answer and still not know was was the problem.
I hope some one can answer the clear questions “MrFly79” outlined.

I think every next years its harder to get UE support. More and more people use UE4, more and more question coming here on UE Answers and in Discord UE4 Slackers, but there are not really active professionals anymore who answer questions. And problems often are really crisp and need some professionals to get answers.

Would be nice if EPIC active support on UE Answer Hub like back in 2014-2015, where official answers and support was available here.

6

Did you solve it with a better PC? Like throw better Hardware at the problem and it solves itself? I am faceing the same problem with no solution.

7

Same issue in 4.27.
Nothing changed in game.

Only thing that changed on my machine was changing video card drivers to one Nintendo requires for the Switch SDK.

8

In my case, RenderViewFamily spikes seem to be related exclusively to my NavMesh settings.

For example, I have a scene with a door that opens.
With a static NavMesh setting, the Draw thread runs at constant 4.5ms before, during and after the opening of the door.
As soon as I attach a Nav Modifier component to the door and set NavMesh generation to “Dynamic Modifiers Only”, the Draw thread doubles to 9ms during the opening of the door. All caused by an increase in RenderViewFamily processing time. That is a lot.
Removing the NavModifier component and changing the NAVMesh runtime generation to “Dynamic” yielded almost the same results as “Dynamic Modifiers Only”.

So although I do not see any NavMesh actually rendered in the scene, it seems that it is going into the render thread behind the scenes.

I have played around with the NaVMesh settings but can not really find any logical parameter (Tile size, cell size,…) that lowers this spike significantly.

It seems that if you want some sort of dynamic navmesh, the base cost is extremely high no matter what.

If anybody comes across a solution to optimize, please let us know.