Get physics linear/angular velocity DELAY (2 frames)

[maslenok]

If i get physics vel. of any object, I not have velocity at exact frame, I have a vector at 2 frames before (thats very bad). sory for my English!

[Sean_L]

Hey maslenok,

I’ve got a setup where my actor is printing Get Physics Angular Velocity, but I’m not sure I understand how you are able to tell that the velocity is from 2 frames ago?

Could you provide some more information on how you are comparing the two values? Are you storing the previous angular velocity somewhere?

Is it possible that the velocity in the current frame is the same as the velocity from two frames ago as well?

Thanks

[maslenok]

I noticed a lag of 2 frames when my custom character staying in moving platform.

1. I get linear velocity of overlapped moving platform
2. I add world delta location to my charater used given velocity from platform / delta time.
3. I see when platform change moving direction to opposite vector, my character moved by the old direction has 2 frames, and after that fallow to platform.
4. I triyng reorganize character blueprint many times, but nothing.

[Sean_L]

What I’d like you to do is see if you can recreate the issue in a clean project, as I’m not seeing it on my end after performing a test.

If you are able to reproduce the issue in a clean project, please provide a detailed list of repro steps so I can investigate and reproduce the issue on my end.

Thanks

[maslenok]

So i created clean project with this issue. In level blueprint you can change moving platform animation, for checking delay of moving platform velocity i recommended set t.maxfps in console to 10. WASD, Z, backspace - input of character, just move down to moving flatform. The issue in “controller” blueprint. Version of engine 4.14.2
link for downloading - https://yadi.sk/d/A67LFf5_36vSYB

[Sean_L]

Thanks for providing the project.

I have a couple more questions:

• What exactly are you looking to accomplish? Just so we can make sure there isn’t a more efficient way to get the same results.
• I’m not sure that I’m seeing the same results as you in your test project. What you’re saying is that the platform is moving in a direction, say to the right, but when it “bounces off” (meaning it changes to moving to the left) the player character continues to receive an offset of rightward movement?

[maslenok]

Thanks for helping

1. I’m working on a custom physicaly correct controller, now i want create accurate “friction” with paltform, without any delay on the part of the character.
2. you’re almost right, but when platform chage direction, character continues moving to old direction 2 frames, and after that character move to properly direction with platfrom, i want to character perfectly accurate staying on platform without any “sliding”. If you change max fps to 10, this slide be bigger.
   2017 01 06 00 47 50 - YouTube - in this video you can see character sliding when plafrom change velocity. that because “get physics linear velocity at point” function give not actual velocity vector of platfrom.

I tried solve this problem using “attach to component” function, and this works, but this method not physicaly correct.
Now i solve this problem. I get platform world location at actual and the previous frame, and subtracts one variable from another, and i know actual velocity of any object. But i want to “get physics linear velocity at point” function to work properly in future versions of ue4

[maslenok]

wow, now i solve this issue 100%!
but that does not negate the fact that the function needs to be fixed in the future

[Sean_L]

Glad to hear that you found a solution! I’ll take a closer look at the function and determine if a ticket needs to be entered if it’s not working as expected.

Thanks for your report.