# 4.17 Instanced static mesh collisions react all at once **URL:** \ **Category:** Asset Creation\ **Tags:** UE4-17, unreal-engine, question\ **Created:** [August 10, 2017, 1:19am UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426 "2017-08-10T01:19:33Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![lizzyvam](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@lizzyvam](https://forums.unrealengine.com/u/lizzyvam)\ **Post date:** [August 10, 2017, 1:19am UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/1 "2017-08-10T01:19:33Z")
every collision of instances react all at once. If touch one, all the other instances react. There is no problem in ‘4.16.3’ There is no problem in ‘4.17 PIE’. ‘4.17 Packaged version(Dev,Shipping)’ always has problems. ---
**Author:** ![TJ\_V](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/tj_v/32/1008648_2.png) [@TJ\_V](https://forums.unrealengine.com/u/TJ_V)\ **Post date:** [August 11, 2017, 12:33pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/2 "2017-08-11T12:33:56Z")
Hi lizzyvam, To help me verify what you are seeing, could you provide a screenshot of your blueprint setup? ---
**Author:** ![lizzyvam](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@lizzyvam](https://forums.unrealengine.com/u/lizzyvam)\ **Post date:** [August 11, 2017, 5:48pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/3 "2017-08-11T17:48:32Z")
![204164-twinstickpawn_trace.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/5/c/9/5c9090cacd58dd822ae2a985186139c3cf2fbaef.png) ![204165-instmesh_setting.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/f/1/1/f11eae429e372d945a0145768741cd0628c6bbaf.png) ![204166-416.gif](https://d3kjluh73b9h9o.cloudfront.net/original/4X/8/4/9/849b8d44305299e86e70255dea310e4446b46bde.gif) Hi TJ V, I created a test project. This is the normal state of the ‘4.16’ ‘packaged’ version. ---
**Author:** ![lizzyvam](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@lizzyvam](https://forums.unrealengine.com/u/lizzyvam)\ **Post date:** [August 11, 2017, 5:49pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/4 "2017-08-11T17:49:39Z")
![204167-417.gif](https://d3kjluh73b9h9o.cloudfront.net/original/4X/1/5/4/1545cabad8d36e0c68bafb5a4d8e3d706ad99fcc.gif) And this is an abnormal state of the ‘4.17’ ‘packaged’ version. The problem occurs only in the ‘packaged’ version. ---
**Author:** ![TJ\_V](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/tj_v/32/1008648_2.png) [@TJ\_V](https://forums.unrealengine.com/u/TJ_V)\ **Post date:** [August 11, 2017, 8:21pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/5 "2017-08-11T20:21:29Z")
Thank you for that. I was able to reproduce this so I’ve created [JIRA UE-48361](https://issues.unrealengine.com/issue/UE-48361). Our developers will be investigating further. Follow that link to monitor the status. -TJ ---
**Author:** ![poke1103](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@poke1103](https://forums.unrealengine.com/u/poke1103)\ **Post date:** [September 17, 2017, 11:24pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/6 "2017-09-17T23:24:51Z")
This is not a duplicate… I opened up version 4.18-staging and this bug is yet to be fixed. Stop pushing back a mistake which is so huge it literally breaks many people’s games. ---
**Author:** ![anonymous\_user\_565e242f](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_565e242f](https://forums.unrealengine.com/u/anonymous_user_565e242f)\ **Post date:** [September 18, 2017, 2:24pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/7 "2017-09-18T14:24:52Z")
Hi Poke1103, keep in mind 4.18 is not currently including any fixes so it’s mostly 4.17.2, as the branch is in lockdown for now… ---
**Author:** ![poke1103](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@poke1103](https://forums.unrealengine.com/u/poke1103)\ **Post date:** [September 27, 2017, 3:43pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/8 "2017-09-27T15:43:07Z")
Michel, I just wanted to let you know there is another issue which has been around for a while now. It’s a easy fix… Please check this: [https://answers.unrealengine.com/questions/574651/foliagecomponent-hitresult-sometimes-returns-inval.html](https://answers.unrealengine.com/questions/574651/foliagecomponent-hitresult-sometimes-returns-inval.html) Basically, when you do a linetrace to a instance, if you have more than int16 number of instances, it will return a negative value (obviously because int16 has a maximum) I have changed it to int32 on my end, but I feel like this could be useful to many other people in the future and its not difficult to change. ---
**Author:** ![anonymous\_user\_565e242f](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_565e242f](https://forums.unrealengine.com/u/anonymous_user_565e242f)\ **Post date:** [September 27, 2017, 4:00pm UTC](https://forums.unrealengine.com/t/4-17-instanced-static-mesh-collisions-react-all-at-once/401426/9 "2017-09-27T16:00:03Z")
this was probably done like this to save on memory, which mean we would have to handle this value as we do for the instance buffer (i.e based on instance count, we use a 16 bits buffer or a 32 bits buffer). We’ll have to see what would be the best way of handling this.