# Issue with FMOD\_ChannelGroup\_Set3DAttributes
**URL:** https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806
**Category:** FMOD Engine
**Created:** [April 4, 2018, 7:15pm UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806 "2018-04-04T19:15:19Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@barrin](https://qa.fmod.com/u/barrin)
#### Post date: [April 4, 2018, 7:15pm UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806/1 "2018-04-04T19:15:19Z")
Hi,
We have a 2D engine, using FMOD 5 Low Level Api. We have issues when calling FMOD\_ChannelGroup\_Set3DAttributes.
We create a channelgroup (children of the master channelgroup) for each char, and attach the playing sounds on the char. To avoid looping over all the current playing channels, we call FMOD\_ChannelGroup\_Set3DAttributes to set the new char’s coordinate to let FMOD update all the playing channels. But we are having trouble, everytime we call FMOD\_ChannelGroup\_Set3DAttributes we get this error:
FMOD\_ERR\_NEEDS3D
Btw, all the sounds in the channels playing on the channelgroup are 3D and created with 3D flags.
Thanks in advance.
---
### Author:  [@cameron-fmod](https://qa.fmod.com/u/cameron-fmod)
#### Post date: [April 9, 2018, 5:25am UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806/2 "2018-04-09T05:25:06Z")
By default ChannelGroups are created as 2D, to change them to 3D you will need to use ChannelGroup::setMode with the flag FMOD\_3D.
[https://fmod.com/resources/documentation-api?page=content/generated/FMOD\_ChannelGroup\_SetMode.html#/](https://fmod.com/resources/documentation-api?page=content/generated/FMOD_ChannelGroup_SetMode.html#/)
---
### Author:  [@barrin](https://qa.fmod.com/u/barrin)
#### Post date: [May 10, 2018, 7:40pm UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806/3 "2018-05-10T19:40:09Z")
> [@](#):
>
> By default ChannelGroups are created as 2D, to change them to 3D you will need to use ChannelGroup::setMode with the flag FMOD\_3D.
>
> [https://fmod.com/resources/documentation-api?page=content/generated/FMOD\_ChannelGroup\_SetMode.html#/](https://fmod.com/resources/documentation-api?page=content/generated/FMOD_ChannelGroup_SetMode.html#/)
Reply added with more info. Code snippet is not working correctly, sorry! Thank you Cameron.
---
### Author:  [@barrin](https://qa.fmod.com/u/barrin)
#### Post date: [May 7, 2018, 9:41pm UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806/4 "2018-05-07T21:41:18Z")
Hi,
We resolved this now, can properly set 3D Channel Groups using FMOD\_ChannelGroup\_Set3DAttributes.
Now we have another issue. The panning works correctly, it calculates properly the position of the source against the listener. The issue is that attenuation is not being made, the sound always returns 1 on FMOD\_Channel\_GetAudibility even at high distances from the listener.
We tested this using FMOD\_Channel\_Set3DAttributes on the playing channel and the attenuation works correctly. But our desired functionality is to control each “source” (moving source) with a channelgroup for recursive sound update.
Thanks.
---
### Author:  [@cameron-fmod](https://qa.fmod.com/u/cameron-fmod)
#### Post date: [May 10, 2018, 3:36am UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806/5 "2018-05-10T03:36:51Z")
> [@](#):
>
> Hi,
>
> We resolved this now, can properly set 3D Channel Groups using FMOD\_ChannelGroup\_Set3DAttributes.
>
> Now we have another issue. The panning works correctly, it calculates properly the position of the source against the listener. The issue is that attenuation is not being made, the sound always returns 1 on FMOD\_Channel\_GetAudibility even at high distances from the listener.
>
> We tested this using FMOD\_Channel\_Set3DAttributes on the playing channel and the attenuation works correctly. But our desired functionality is to control each “source” (moving source) with a channelgroup for recursive sound update.
>
> Thanks.
The audibility value should change each time you call it, I have got it working testing it here. Can you share some of the code you are using for this?
---
### Author:  [@barrin](https://qa.fmod.com/u/barrin)
#### Post date: [May 10, 2018, 2:15pm UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806/6 "2018-05-10T14:15:02Z")
Issue #1: Set3DAttributes not applying the attenuation
This is the code that plays a sound under a character’s channel group:
'Plays a sound on the master channel group (game events for characters)
Public Function PlayOnChar(ByVal intSoundIndex As Integer, ByVal intCharIndex As Integer) As Long
On Error GoTo ErrorHandler
If (intSoundIndex \<= 0) Or (intSoundIndex \> mNumSounds) Then Exit Function
If Not SoundData(intSoundIndex).Buffer.Loaded Then Exit Function
Dim lngResult As Long
Dim lngFMODChannel As Long
Dim lngChannelGroup As Long
If SoundData(intSoundIndex).Buffer.Is3D Then
```
Dim Pos As FMOD_VECTOR
If Not frmMain.Engine.Char_Coord_Get(intCharIndex, Pos.X, Pos.Y) Then Exit Function
Pos.Z = 0
lngChannelGroup = frmMain.Engine.Char_Sound_ChannelGroup_Get(intCharIndex)
If lngChannelGroup = 0 Then
lngResult = FMOD_System_CreateChannelGroup(mFMODSystem, vbNullString, lngChannelGroup)
If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_System_CreateChannelGroup (Char) Failed")
lngResult = FMOD_ChannelGroup_SetMode(lngChannelGroup, FMOD_3D)
If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_ChannelGroup_SetMode (Char) Failed")
lngResult = FMOD_ChannelGroup_Set3DAttributes(lngChannelGroup, VarPtr(Pos), 0, 0)
If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_ChannelGroup_Set3DAttributes (Char) Failed")
lngResult = FMOD_ChannelGroup_AddGroup(mFMODSoundChannelGroup, lngChannelGroup, 0, 0)
If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_ChannelGroup_AddGroup (Char) Failed")
Call frmMain.Engine.Char_Sound_ChannelGroup_Set(intCharIndex, lngChannelGroup)
End If
lngResult = FMOD_System_PlaySound(mFMODSystem, SoundData(intSoundIndex).Buffer.handle, lngChannelGroup, 0, lngFMODChannel)
If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "Error while playing sound #" & intSoundIndex)
'Always returns 1
Dim sngAudibility As Single
FMOD_Channel_GetAudibility lngFMODChannel, sngAudibility
Debug.Print sngAudibility
```
Else
lngResult = FMOD\_System\_PlaySound(mFMODSystem, SoundData(intSoundIndex).Buffer.handle, mFMODSoundChannelGroup, 0, lngFMODChannel)
If lngResult \<\> FMOD\_OK Then Call Err.Raise(lngResult, , “Error while playing sound #” & intSoundIndex)
End If
PlayOnChar = lngFMODChannel
Exit Function
ErrorHandler:
Call Client\_LogError(“clsSoundEngine-\>PlayOnChar”, Err.Description, Err.Number)
End Function
Issue N2: The documentation says that when a channelgroup is released it moves the channels to the master’s channelgroup. Is this behaviour still applied to channelgroups that have a “master” channelgroup added? (Like the example above)?
For now we are using this code to transfer the channelgroup’s channels to the desired channel group.
'Transfers a group to the local sound channel group (not the “master” channelgroup)
Public Function TransferGroup(ByVal lngFMODChannelGroup As Long) As Boolean
Dim lngResult As Long
Dim lngNumPlaying As Long
lngResult = FMOD\_ChannelGroup\_GetNumChannels(lngFMODChannelGroup, lngNumPlaying)
If lngResult \<\> FMOD\_OK Then Call Err.Raise(lngResult, , “FMOD\_ChannelGroup\_GetNumPlaying Failed”)
If lngNumPlaying \> 0 Then
Dim i As Long, lngFMODChannel As Long
```
For i = 0 To lngNumPlaying - 1
lngResult = FMOD_ChannelGroup_GetChannel(lngFMODChannelGroup, i, lngFMODChannel)
If lngResult = FMOD_OK Then
'Transfer the channel to the local sound channelgroup
lngResult = FMOD_Channel_SetChannelGroup(lngFMODChannel, mFMODSoundChannelGroup)
If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_Channel_SetGroup Failed")
End If
Next i
```
End If
'Release the old channelgroup
Call Audio\_ReleaseChannelGroup(lngFMODChannelGroup)
End Function
---
### Author:  [@cameron-fmod](https://qa.fmod.com/u/cameron-fmod)
#### Post date: [May 11, 2018, 5:50am UTC](https://qa.fmod.com/t/issue-with-fmod-channelgroup-set3dattributes/13806/7 "2018-05-11T05:50:54Z")
> [@](#):
>
> Issue #1: Set3DAttributes not applying the attenuation
>
> This is the code that plays a sound under a character’s channel group:
>
> 'Plays a sound on the master channel group (game events for characters)
> Public Function PlayOnChar(ByVal intSoundIndex As Integer, ByVal intCharIndex As Integer) As Long
>
> On Error GoTo ErrorHandler
>
> If (intSoundIndex \<= 0) Or (intSoundIndex \> mNumSounds) Then Exit Function
> If Not SoundData(intSoundIndex).Buffer.Loaded Then Exit Function
>
> Dim lngResult As Long
> Dim lngFMODChannel As Long
> Dim lngChannelGroup As Long
>
> If SoundData(intSoundIndex).Buffer.Is3D Then
>
> ```
> Dim Pos As FMOD_VECTOR
>
> If Not frmMain.Engine.Char_Coord_Get(intCharIndex, Pos.X, Pos.Y) Then Exit Function
> Pos.Z = 0
>
> lngChannelGroup = frmMain.Engine.Char_Sound_ChannelGroup_Get(intCharIndex)
>
> If lngChannelGroup = 0 Then
> lngResult = FMOD_System_CreateChannelGroup(mFMODSystem, vbNullString, lngChannelGroup)
> If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_System_CreateChannelGroup (Char) Failed")
>
> lngResult = FMOD_ChannelGroup_SetMode(lngChannelGroup, FMOD_3D)
> If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_ChannelGroup_SetMode (Char) Failed")
>
> lngResult = FMOD_ChannelGroup_Set3DAttributes(lngChannelGroup, VarPtr(Pos), 0, 0)
> If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_ChannelGroup_Set3DAttributes (Char) Failed")
>
> lngResult = FMOD_ChannelGroup_AddGroup(mFMODSoundChannelGroup, lngChannelGroup, 0, 0)
> If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_ChannelGroup_AddGroup (Char) Failed")
>
> Call frmMain.Engine.Char_Sound_ChannelGroup_Set(intCharIndex, lngChannelGroup)
> End If
>
> lngResult = FMOD_System_PlaySound(mFMODSystem, SoundData(intSoundIndex).Buffer.handle, lngChannelGroup, 0, lngFMODChannel)
> If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "Error while playing sound #" & intSoundIndex)
>
> 'Always returns 1
> Dim sngAudibility As Single
> FMOD_Channel_GetAudibility lngFMODChannel, sngAudibility
> Debug.Print sngAudibility
>
> ```
>
> Else
> lngResult = FMOD\_System\_PlaySound(mFMODSystem, SoundData(intSoundIndex).Buffer.handle, mFMODSoundChannelGroup, 0, lngFMODChannel)
> If lngResult \<\> FMOD\_OK Then Call Err.Raise(lngResult, , “Error while playing sound #” & intSoundIndex)
> End If
>
> PlayOnChar = lngFMODChannel
>
> Exit Function
>
> ErrorHandler:
> Call Client\_LogError(“clsSoundEngine-\>PlayOnChar”, Err.Description, Err.Number)
>
> End Function
>
> Issue N2: The documentation says that when a channelgroup is released it moves the channels to the master’s channelgroup. Is this behaviour still applied to channelgroups that have a “master” channelgroup added? (Like the example above)?
>
> For now we are using this code to transfer the channelgroup’s channels to the desired channel group.
>
> 'Transfers a group to the local sound channel group (not the “master” channelgroup)
> Public Function TransferGroup(ByVal lngFMODChannelGroup As Long) As Boolean
>
> Dim lngResult As Long
> Dim lngNumPlaying As Long
>
> lngResult = FMOD\_ChannelGroup\_GetNumChannels(lngFMODChannelGroup, lngNumPlaying)
> If lngResult \<\> FMOD\_OK Then Call Err.Raise(lngResult, , “FMOD\_ChannelGroup\_GetNumPlaying Failed”)
>
> If lngNumPlaying \> 0 Then
> Dim i As Long, lngFMODChannel As Long
>
> ```
> For i = 0 To lngNumPlaying - 1
> lngResult = FMOD_ChannelGroup_GetChannel(lngFMODChannelGroup, i, lngFMODChannel)
>
> If lngResult = FMOD_OK Then
> 'Transfer the channel to the local sound channelgroup
> lngResult = FMOD_Channel_SetChannelGroup(lngFMODChannel, mFMODSoundChannelGroup)
> If lngResult <> FMOD_OK Then Call Err.Raise(lngResult, , "FMOD_Channel_SetGroup Failed")
> End If
> Next i
>
> ```
>
> End If
>
> 'Release the old channelgroup
> Call Audio\_ReleaseChannelGroup(lngFMODChannelGroup)
>
> End Function
After digging into this deeper, it does appear to be a bug with ChannelGroup audibility where the attenuation isn’t taken into account properly.
We have logged this as a task and will have a fix in a future release.
As for the second issue: if you release a channelGroup, anything that was attached to it will always be routed through the Master channel group. If you want it to be routed somewhere in particular other than the Master, you will have to do this manually.