For vehicle physics in Unreal Engine, should use always atan2 instead of atan? #UnrealEngine #Programming #Gamedev
This:
mSlipAngle = FMath::Atan2(mLocalVelocity.Y, absForwardVelocity)
Instead of:
mSlipAngle = FMath::Atan(mLocalVelocity.Y / (absForwardVelocity + FGearUtility::epsilon));
This:
mSlipAngle = FMath::Atan2(mLocalVelocity.Y, absForwardVelocity)
Instead of:
mSlipAngle = FMath::Atan(mLocalVelocity.Y / (absForwardVelocity + FGearUtility::epsilon));
October 31, 2025 at 7:37 PM
For vehicle physics in Unreal Engine, should use always atan2 instead of atan? #UnrealEngine #Programming #Gamedev
This:
mSlipAngle = FMath::Atan2(mLocalVelocity.Y, absForwardVelocity)
Instead of:
mSlipAngle = FMath::Atan(mLocalVelocity.Y / (absForwardVelocity + FGearUtility::epsilon));
This:
mSlipAngle = FMath::Atan2(mLocalVelocity.Y, absForwardVelocity)
Instead of:
mSlipAngle = FMath::Atan(mLocalVelocity.Y / (absForwardVelocity + FGearUtility::epsilon));
Any better way to get the same?
bool isAccel = (mAccel - aOldAccel) > 0.01f;
aOldAccel = FMath::Lerp(aOldAccel, mAccel, 0.2f);
debug = isAccel ? 222.0f : 0.0f;
If Throttle goes up = 222.0, if stays/down = 0.0f
Added "0.01f;" as tolerance in bool or not works.
#UnrealEngine #Gamedev #Indiedev
bool isAccel = (mAccel - aOldAccel) > 0.01f;
aOldAccel = FMath::Lerp(aOldAccel, mAccel, 0.2f);
debug = isAccel ? 222.0f : 0.0f;
If Throttle goes up = 222.0, if stays/down = 0.0f
Added "0.01f;" as tolerance in bool or not works.
#UnrealEngine #Gamedev #Indiedev
November 21, 2024 at 12:17 PM
Any better way to get the same?
bool isAccel = (mAccel - aOldAccel) > 0.01f;
aOldAccel = FMath::Lerp(aOldAccel, mAccel, 0.2f);
debug = isAccel ? 222.0f : 0.0f;
If Throttle goes up = 222.0, if stays/down = 0.0f
Added "0.01f;" as tolerance in bool or not works.
#UnrealEngine #Gamedev #Indiedev
bool isAccel = (mAccel - aOldAccel) > 0.01f;
aOldAccel = FMath::Lerp(aOldAccel, mAccel, 0.2f);
debug = isAccel ? 222.0f : 0.0f;
If Throttle goes up = 222.0, if stays/down = 0.0f
Added "0.01f;" as tolerance in bool or not works.
#UnrealEngine #Gamedev #Indiedev
Cool cool, updated Jetbrains Rider and they've forcefully reenabled their "AI Language Model" autocomplete which , surprise surprise, immediately starts suggesting plausible-looking nonsense
(the suggestion here will never return a negative for the sign, even if the input is negative)
(the suggestion here will never return a negative for the sign, even if the input is negative)
August 4, 2026 at 12:04 PM
Cool cool, updated Jetbrains Rider and they've forcefully reenabled their "AI Language Model" autocomplete which , surprise surprise, immediately starts suggesting plausible-looking nonsense
(the suggestion here will never return a negative for the sign, even if the input is negative)
(the suggestion here will never return a negative for the sign, even if the input is negative)
I need to use: FMath::Pow(mTargetSteeringInput, 2) but then result is always positive. This works:
FMath::Pow(mTargetSteeringInput, 2) * FMath::Sign(mTargetSteeringInput)
But, Is the correct way? Better alternatives?
#UnrealEngine #UE5 #Gamedev #Indiedev
FMath::Pow(mTargetSteeringInput, 2) * FMath::Sign(mTargetSteeringInput)
But, Is the correct way? Better alternatives?
#UnrealEngine #UE5 #Gamedev #Indiedev
November 1, 2024 at 1:40 PM
I need to use: FMath::Pow(mTargetSteeringInput, 2) but then result is always positive. This works:
FMath::Pow(mTargetSteeringInput, 2) * FMath::Sign(mTargetSteeringInput)
But, Is the correct way? Better alternatives?
#UnrealEngine #UE5 #Gamedev #Indiedev
FMath::Pow(mTargetSteeringInput, 2) * FMath::Sign(mTargetSteeringInput)
But, Is the correct way? Better alternatives?
#UnrealEngine #UE5 #Gamedev #Indiedev
Ok, so optimized to: x*abs(x) , this:
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
Guess is the best way now? If anything better, let me know.
Credits to @xblasco.bsky.social
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
Guess is the best way now? If anything better, let me know.
Credits to @xblasco.bsky.social
I need to use: FMath::Pow(mTargetSteeringInput, 2) but then result is always positive. This works:
FMath::Pow(mTargetSteeringInput, 2) * FMath::Sign(mTargetSteeringInput)
But, Is the correct way? Better alternatives?
#UnrealEngine #UE5 #Gamedev #Indiedev
FMath::Pow(mTargetSteeringInput, 2) * FMath::Sign(mTargetSteeringInput)
But, Is the correct way? Better alternatives?
#UnrealEngine #UE5 #Gamedev #Indiedev
November 1, 2024 at 2:05 PM
Ok, so optimized to: x*abs(x) , this:
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
Guess is the best way now? If anything better, let me know.
Credits to @xblasco.bsky.social
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
Guess is the best way now? If anything better, let me know.
Credits to @xblasco.bsky.social
More code Shenanigans 😆
The refactored version works, formula clamps to 0-1 but gives slighty different results, but cant find the problem.
frontShare = FMath::Max(0.0f, FMath::Min(1.0f, mTorqueShares[0] -lockRatio *(1.0f -(rearSpeed /frontSpeed )) *mTorqueShares[0]));
Any idea? #UE5 #Programming
The refactored version works, formula clamps to 0-1 but gives slighty different results, but cant find the problem.
frontShare = FMath::Max(0.0f, FMath::Min(1.0f, mTorqueShares[0] -lockRatio *(1.0f -(rearSpeed /frontSpeed )) *mTorqueShares[0]));
Any idea? #UE5 #Programming
February 2, 2025 at 2:00 PM
More code Shenanigans 😆
The refactored version works, formula clamps to 0-1 but gives slighty different results, but cant find the problem.
frontShare = FMath::Max(0.0f, FMath::Min(1.0f, mTorqueShares[0] -lockRatio *(1.0f -(rearSpeed /frontSpeed )) *mTorqueShares[0]));
Any idea? #UE5 #Programming
The refactored version works, formula clamps to 0-1 but gives slighty different results, but cant find the problem.
frontShare = FMath::Max(0.0f, FMath::Min(1.0f, mTorqueShares[0] -lockRatio *(1.0f -(rearSpeed /frontSpeed )) *mTorqueShares[0]));
Any idea? #UE5 #Programming
today in Unreal Has A Node For That Already: mirror vector by normal
(and in c++, it's FMath::GetReflectionVector)
(and in c++, it's FMath::GetReflectionVector)
October 1, 2025 at 3:16 AM
today in Unreal Has A Node For That Already: mirror vector by normal
(and in c++, it's FMath::GetReflectionVector)
(and in c++, it's FMath::GetReflectionVector)
THEY USED ^ TO DO VECTOR CROSS PRODUCT
NO ONE DOES THAT JUST DO FMATH::CROSS() LIKE A NORMAL PERSON
Oh wait you can't because you used a fuckin robot to guess at "correct" code, so its up to me to fix your fuckin shitty code
God. Hate this. No wonder all of this is illegible
NO ONE DOES THAT JUST DO FMATH::CROSS() LIKE A NORMAL PERSON
Oh wait you can't because you used a fuckin robot to guess at "correct" code, so its up to me to fix your fuckin shitty code
God. Hate this. No wonder all of this is illegible
Asked a co-worker at work how a debug feature is meant to be interpreted and they sent me a screencap of the code
Bitch, no, i want your human ass words. I want your words in order to save *all* of us time. I've been reading the code for hours already, fucker. Explain your work, you genai fuck.
Bitch, no, i want your human ass words. I want your words in order to save *all* of us time. I've been reading the code for hours already, fucker. Explain your work, you genai fuck.
July 22, 2026 at 10:44 PM
THEY USED ^ TO DO VECTOR CROSS PRODUCT
NO ONE DOES THAT JUST DO FMATH::CROSS() LIKE A NORMAL PERSON
Oh wait you can't because you used a fuckin robot to guess at "correct" code, so its up to me to fix your fuckin shitty code
God. Hate this. No wonder all of this is illegible
NO ONE DOES THAT JUST DO FMATH::CROSS() LIKE A NORMAL PERSON
Oh wait you can't because you used a fuckin robot to guess at "correct" code, so its up to me to fix your fuckin shitty code
God. Hate this. No wonder all of this is illegible
FMath::IsNearlyEqual() is your buddy here
April 14, 2026 at 9:02 PM
FMath::IsNearlyEqual() is your buddy here
🔍 Floats are liars!
Comparing floats in Unreal? Be careful — Value == 1.f might fail due to IEEE-754 imprecision.
✅ Use FMath::IsNearlyEqual() or IsNearlyZero()
🎨 In Blueprints? Use the “Nearly Equal” node.
#UnrealEngine #GameDev #CPP
Comparing floats in Unreal? Be careful — Value == 1.f might fail due to IEEE-754 imprecision.
✅ Use FMath::IsNearlyEqual() or IsNearlyZero()
🎨 In Blueprints? Use the “Nearly Equal” node.
#UnrealEngine #GameDev #CPP
May 19, 2025 at 12:48 AM
🔍 Floats are liars!
Comparing floats in Unreal? Be careful — Value == 1.f might fail due to IEEE-754 imprecision.
✅ Use FMath::IsNearlyEqual() or IsNearlyZero()
🎨 In Blueprints? Use the “Nearly Equal” node.
#UnrealEngine #GameDev #CPP
Comparing floats in Unreal? Be careful — Value == 1.f might fail due to IEEE-754 imprecision.
✅ Use FMath::IsNearlyEqual() or IsNearlyZero()
🎨 In Blueprints? Use the “Nearly Equal” node.
#UnrealEngine #GameDev #CPP
The Start of Something New?
I'm excited to launch this account dedicated to teaching Cambridge AS & A Level Mathematics (9709) and Further Mathematics (9231) for the 2026-2027 exams!
#manim #math #alevels #alevel #fmath #furthermath #furthermaths #mathematic #cambridge #trending
I'm excited to launch this account dedicated to teaching Cambridge AS & A Level Mathematics (9709) and Further Mathematics (9231) for the 2026-2027 exams!
#manim #math #alevels #alevel #fmath #furthermath #furthermaths #mathematic #cambridge #trending
October 1, 2025 at 1:26 PM
The Start of Something New?
I'm excited to launch this account dedicated to teaching Cambridge AS & A Level Mathematics (9709) and Further Mathematics (9231) for the 2026-2027 exams!
#manim #math #alevels #alevel #fmath #furthermath #furthermaths #mathematic #cambridge #trending
I'm excited to launch this account dedicated to teaching Cambridge AS & A Level Mathematics (9709) and Further Mathematics (9231) for the 2026-2027 exams!
#manim #math #alevels #alevel #fmath #furthermath #furthermaths #mathematic #cambridge #trending
If you're using the #UnrealEngine plugin Motion made by Kia Armani and you want to add some inertia to the camera rotation, you could do it like this: https://gist.github.com/Plimsky/925aacdcad0e9d259f690efe562d7bdf
#UE5 #gamedev #indiedev #code #cpp
#UE5 #gamedev #indiedev #code #cpp
November 14, 2024 at 3:46 PM
If you're using the #UnrealEngine plugin Motion made by Kia Armani and you want to add some inertia to the camera rotation, you could do it like this: https://gist.github.com/Plimsky/925aacdcad0e9d259f690efe562d7bdf
#UE5 #gamedev #indiedev #code #cpp
#UE5 #gamedev #indiedev #code #cpp
I dunno how UE code works but multiplying a number by its absolute value is what you're looking for I think, since the pow function is slow in comparison, and the absolute value function is like. O(1) or something.
my assumption for UE is:
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
my assumption for UE is:
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
November 1, 2024 at 1:54 PM
I dunno how UE code works but multiplying a number by its absolute value is what you're looking for I think, since the pow function is slow in comparison, and the absolute value function is like. O(1) or something.
my assumption for UE is:
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
my assumption for UE is:
mTargetSteeringInput * FMath::Abs(mTargetSteeringInput)
Best way to detect if a value increases or decreases?
What i have now:
-
bool isLngFrictionUp = (mLngFriction - aLastLngF) > 0.001f;
aLastLngF = FMath::Lerp(aLastLngF, mLngFriction, 0.1f);
float lerpLngF = isLngFrictionUp ? 1.0f : 2.0f;
-
What you think? Any optimization/correction?
What i have now:
-
bool isLngFrictionUp = (mLngFriction - aLastLngF) > 0.001f;
aLastLngF = FMath::Lerp(aLastLngF, mLngFriction, 0.1f);
float lerpLngF = isLngFrictionUp ? 1.0f : 2.0f;
-
What you think? Any optimization/correction?
June 20, 2025 at 4:06 PM
Best way to detect if a value increases or decreases?
What i have now:
-
bool isLngFrictionUp = (mLngFriction - aLastLngF) > 0.001f;
aLastLngF = FMath::Lerp(aLastLngF, mLngFriction, 0.1f);
float lerpLngF = isLngFrictionUp ? 1.0f : 2.0f;
-
What you think? Any optimization/correction?
What i have now:
-
bool isLngFrictionUp = (mLngFriction - aLastLngF) > 0.001f;
aLastLngF = FMath::Lerp(aLastLngF, mLngFriction, 0.1f);
float lerpLngF = isLngFrictionUp ? 1.0f : 2.0f;
-
What you think? Any optimization/correction?
Never compare floats directly.
Use the function that your engine gave you, or use an epsilon (nerd name for "a kinda small number).
Unity: Mathf.Approximately(a, b)
Unreal: FMath::IsNearlyEqual(a, b)
With an epsilon: abs(a - b) < 0.0001
Use the function that your engine gave you, or use an epsilon (nerd name for "a kinda small number).
Unity: Mathf.Approximately(a, b)
Unreal: FMath::IsNearlyEqual(a, b)
With an epsilon: abs(a - b) < 0.0001
April 18, 2025 at 6:56 PM
Never compare floats directly.
Use the function that your engine gave you, or use an epsilon (nerd name for "a kinda small number).
Unity: Mathf.Approximately(a, b)
Unreal: FMath::IsNearlyEqual(a, b)
With an epsilon: abs(a - b) < 0.0001
Use the function that your engine gave you, or use an epsilon (nerd name for "a kinda small number).
Unity: Mathf.Approximately(a, b)
Unreal: FMath::IsNearlyEqual(a, b)
With an epsilon: abs(a - b) < 0.0001
My favorite way to control #UnrealEngine Timelines is with a custom function SetDuration. Which scales the PlayRate to match a given Duration.
This will make any Timeline of *any Length* play for the given Duration.
I prefer to then author my curves from 0-1.
#GameDev
github.com/BenVlodgi/UE...
This will make any Timeline of *any Length* play for the given Duration.
I prefer to then author my curves from 0-1.
#GameDev
github.com/BenVlodgi/UE...
February 8, 2024 at 5:14 PM
My favorite way to control #UnrealEngine Timelines is with a custom function SetDuration. Which scales the PlayRate to match a given Duration.
This will make any Timeline of *any Length* play for the given Duration.
I prefer to then author my curves from 0-1.
#GameDev
github.com/BenVlodgi/UE...
This will make any Timeline of *any Length* play for the given Duration.
I prefer to then author my curves from 0-1.
#GameDev
github.com/BenVlodgi/UE...
Of course, similar problem trying to create a basic expression evaluator node e.g. with FMath::Eval.
It feels like this comment is pointing to some nontrivial missing steps. E.g. for expr node, dealing with an AST would probably be worse? To the extent that the proof of concept doesn't mean much.
It feels like this comment is pointing to some nontrivial missing steps. E.g. for expr node, dealing with an AST would probably be worse? To the extent that the proof of concept doesn't mean much.
February 24, 2025 at 7:30 PM
Of course, similar problem trying to create a basic expression evaluator node e.g. with FMath::Eval.
It feels like this comment is pointing to some nontrivial missing steps. E.g. for expr node, dealing with an AST would probably be worse? To the extent that the proof of concept doesn't mean much.
It feels like this comment is pointing to some nontrivial missing steps. E.g. for expr node, dealing with an AST would probably be worse? To the extent that the proof of concept doesn't mean much.
I have narrowed it down to some form of math/boolean evaluation problem. Here is a minimal reproduction on Win64 Development Editor configuration:
Comparison A resolves to True
Comparison B resolves to False
They should both fail!
Comparison A resolves to True
Comparison B resolves to False
They should both fail!
September 7, 2025 at 12:02 AM
I have narrowed it down to some form of math/boolean evaluation problem. Here is a minimal reproduction on Win64 Development Editor configuration:
Comparison A resolves to True
Comparison B resolves to False
They should both fail!
Comparison A resolves to True
Comparison B resolves to False
They should both fail!
Ran into this again last night on UE 4.27 so I guess it's extra broken lol. I received another VS update after that and an OS update so who knows how screwed up my toolchains are now. My fix was to make a custom NAN macro that maps to ((float)FMath::Sqrt(-1)) and use it for all compilers/versions.
Wheeeew an update to VS 2017 broke the C Runtime's NAN macro on old versions of UE4. That was weird... FMath::Sqrt(-1) to the rescue I guess?
July 9, 2025 at 9:32 PM
Ran into this again last night on UE 4.27 so I guess it's extra broken lol. I received another VS update after that and an OS update so who knows how screwed up my toolchains are now. My fix was to make a custom NAN macro that maps to ((float)FMath::Sqrt(-1)) and use it for all compilers/versions.
Wheeeew an update to VS 2017 broke the C Runtime's NAN macro on old versions of UE4. That was weird... FMath::Sqrt(-1) to the rescue I guess?
July 8, 2025 at 3:45 AM
Wheeeew an update to VS 2017 broke the C Runtime's NAN macro on old versions of UE4. That was weird... FMath::Sqrt(-1) to the rescue I guess?
yes!!! I should have known fMath would be the one to get the reference!! You just made my evening
August 22, 2025 at 5:13 AM
yes!!! I should have known fMath would be the one to get the reference!! You just made my evening