Beta 6 Landscape Collision Bug, Chance It is Unrelated to PhysX 3.3

#Please note

(I’m pretty excited that I think I know what the issue is)

I feel I have reasonable forensic evidence that this issue may not be PhysX related (hopefully Jack Porter will like this fact)

Please see below and also see my video for details of how this seems related to a new beta6 feature of a certain world Z aligned downpush that occurs after landing from jumping.

Dear Friends at Epic,

As Alexander requested I have createda new topic for my current issue with Landscapes.


When my character roams around the map, there seem to be distinct places where the character falls through the map.

I have extensively played using only just this 1 map, and this 1 landscape that I have made,

and I did not have this issue in beta4 or beta5.

#Very Beta6-Specific

I work with my UE4 project every day and am hardly ever in the editor,

I am mostly in-game moving the characters around, and coding in the c++

So I definitely think I would have noticed falling through this 1 spot (and there are others) if it was a bug present in beta4 or beta5.

I have used characters to roam this terrain daily for past 4 months,

and only in beta6 have I experienced this specific fall through areas.

In beta4,

I had NO issues and felt landscapes were perfect and awesome and sooo very nice and bug-free.

In beta5,

I was finding my character getting randomly stuck on stuff, and when I played with the collision MIP, then the landscape would sometimes lose all collision.

But in beta5 character was not falling through map in very specific places ever

Here is link to my UDN post and Jack’s replies to Beta5 PhysX 3.3 related issues:

Now in beta6,

there is this new distinct issue of specific spots on the very same unchanged map allowing player to fall through

Again the most notable thing here:

my landscape has not changed since beta4, when all was perfect, as I've been doing mostly coding and animations.

So whatever has changed the way collsion works with landscape has nothing to do with any changes I’ve made cause I have not made any :slight_smile:


This is only on Epic’s drop box, it is not public at all :slight_smile:


#Video Explanation

I repro’ed falling through the same spot on my map 3 times using my main map

Then I imported the .raw file, a repro-able thing you can try, and produced the same issues in the same spot within seconds.

Again, I never ever noticed this in beta4, and had different issues in beta5,

This one spot in this video was never an issue before beta6, and I know there are other spots as well.

But you should be able to reproduce the one spot in this video pretty easily!

#Video Expanded Analysis

It is worth noting that my 3rd repro-attempt took me longer, though I did all these videos consecutively and was trying to hone in on the one spot.

So you may have to try for a bit.

When I did the 4th attempt with the .raw import I got it pretty much immediately.

But as far as the actual technical issue is consider it is worth noting that it takes a bit of effort to reproduce at times.

(I have no idea all the factors that are involved, but this is my observation)

#Possible Non-PhysX Reason: Jumping seems to help the repro happen faster

Skylar Breen (rocket user) noted that when a character lands there is a new downward push in beta 6

I wonder if this new downward push is pushing the Character through the landscape surface collision?

in both my 3rd and 4th attempts, the repro happens right after jumping (see video please)

#It Really Does Seem Jumping Related

Correction: I repro the fall-through in all 4 cases right after or soon after a jump,

and the new downward push in beta6 might still be active at that point of fall through.

During repro-attempt 3, I could not fall through until I jumped in the one spot I had honed in on

#Skylar Breen’s Video of the New Beta6 Jump Down Push

Skylar has a video of what I think the issue might be related to that is non Physx

this video is unlisted on you tube, so should be easy to review fast

I am referring to the down push ( World Z) that is occurring each time Skylar’s character lands while not properly aligned with World Z

I am supposing that at landscape angles, this down push is being applied,

and pushing the character through the landscape

I have no way to verify this, but maybe you can nullify this behavior on your end

after having repro’ed the issue with my landscape .raw in the spot I show in my video?


I had uploaded my landscape .raw file and a .umap for the beta5 landscape issues


so you could do what I do for the last part of video:

  • import the .raw into a new level, sizing the landscape to fit

  • add any landscape material of your choice and build lighting

  • find the spot I show in the videos

  • you should be able to reproduce the fall-through within a few moments, could try jumping as necessary


my project started with C++ third person shooter so that would be the closest repro case

#Final Summary & My Conclusions From My Video

If you review my video carefully, only in attempt 3 does it take me a while to repro the issue

And only in attempt 3 do I not jump for a long time

And on the FIRST JUMP I do in attempt 3, the repro occurs.

I really think this might be related to character capsule’s and the new jump land downpush thing Skylar noted as well.

Hope this Makes Jack’s day brighter :slight_smile: (cause it does not seem physX 3.3 related)

Again this is Beta6 the Voyager

#Let Me Know

Let me know if there’s anything you’d like me to try on my end!



#Impart Velocity

I tried unchecking this options in my character but there was no change in the issue


#I Tried Overirding AdjustFloorHeight()

I tried overriding

void UVictoryCharMoveComp::AdjustFloorHeight()
    //Override and do nothing - fixes the unwanted Z move down added in beta 6

but that did not stop the fall through

Thanks Jack!

“I still believe the bug is probably related to the PhysX 3.3 upgrade, but I’ve asked our QA guys to do as much testing as they can to find out exactly what change has triggered the bug”

Yes I have come to that conclusion as well after testing using a custom movement component and disabling several different jump and gravity mechanics.

#Let Me Know

Let me know what I can do to help you further with this!

I can’t wait till Landscapes are fully fixed because in my opinion they look awesome and are a key feature of my game and a huge aspect of the UE4 engine for me :slight_smile:


Hi Rama,

Happy new year and thanks for your patience with this bug and for all your testing!

In my testing I’ve never been able to get stuck with your map, but I have seen the issue falling through but not always when jumping. Sometimes just walking up the slope and falling down it is enough. Taking your heightmap and removing all except one of the landscape components, I have confirmed that it’s happening inside a single component and isn’t related to the boundaries between two components.

I still believe the bug is probably related to the PhysX 3.3 upgrade, but I’ve asked our QA guys to do as much testing as they can to find out exactly what change has triggered the bug.


#This Issue Has Been Totally Fixed As of Engine Version 4.3 !

I have wonderful news for you all!

Jack Porter has fixed the Landscape Collision Issue, with help from Zak Middleton!

Jack Porter deserves many flowers and butterflies sent in his general direction!

And, best of all,

This fix is live as of 4.3!

#Solution Thread



This is a question from the beta version of the engine. We are marking this answered for tracking purposes. If you are experiencing an issue similar to this please post a new question.

Thank you.