blender/blender-manual
23
23
Fork 104
Code Issues 74 Pull Requests 6 Projects 1 Releases Wiki Activity

Mantaflow Object Initial Velocity Local Coordinates. #74818

New Issue
Closed
opened 2020-03-16 17:17:27 +01:00 by RAM · 15 comments
RAM commented 2020-03-16 17:17:27 +01:00
Copy Link

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: Quadro P4000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.70

Blender Version
Broken: version: 2.82 (sub 7), branch: master, commit date: 2020-02-12 16:20, hash: blender/blender@77d23b0bd7

Short description of error
Documentation https://docs.blender.org/manual/en/latest/physics/fluid/type/flow.html#initial-velocity states that:

Initial Velocity: When enabled, the fluid will inherit the momentum of the flow source.

This is not true for all sub-items - Initial X Y and Z velocity will affect stationary object.

Initial X, Y, Z: Initial velocity along X, Y, Z coordinates. Can be used in addition to the initial velocity along the Normal.

It is not clear in what coordinate space this will affect simulation.

Exact steps for others to reproduce the error
#74818.blend

  • Open file
  • Bake and run simulation.

Flow source is rotated and has set initial velocity in Z.
One may expect that flow velocity vector will be affected by flow source rotation.

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: Quadro P4000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.70 **Blender Version** Broken: version: 2.82 (sub 7), branch: master, commit date: 2020-02-12 16:20, hash: `blender/blender@77d23b0bd7` **Short description of error** Documentation https://docs.blender.org/manual/en/latest/physics/fluid/type/flow.html#initial-velocity states that: > Initial Velocity: When enabled, the fluid will inherit the momentum of the flow source. This is not true for all sub-items - Initial X Y and Z velocity will affect stationary object. >Initial X, Y, Z: Initial velocity along X, Y, Z coordinates. Can be used in addition to the initial velocity along the Normal. It is not clear in what coordinate space this will affect simulation. **Exact steps for others to reproduce the error** [#74818.blend](https://archive.blender.org/developer/F8423789/T74818.blend) - Open file - Bake and run simulation. Flow source is rotated and has set initial velocity in Z. One may expect that flow velocity vector will be affected by flow source rotation.
RAM commented 2020-03-16 17:17:27 +01:00
Author
Copy Link

Added subscriber: @CrossmindStudio

Added subscriber: @CrossmindStudio
Richard Antalik commented 2020-03-17 20:51:43 +01:00
Member
Copy Link

Added subscribers: @sebbas, @iss

Added subscribers: @sebbas, @iss
Richard Antalik commented 2020-03-17 20:51:43 +01:00
Member
Copy Link

@sebbas It is not clear to me, if this is working as intended, Can you confirm/close this report?

@sebbas It is not clear to me, if this is working as intended, Can you confirm/close this report?
Ankit Meel commented 2020-03-21 08:48:50 +01:00
Member
Copy Link

Added subscriber: @ankitm

Added subscriber: @ankitm
Ankit Meel commented 2020-03-21 08:48:50 +01:00
Member
Copy Link

https://developer.blender.org/T72949

https://developer.blender.org/T72949
Ankit Meel commented 2020-04-20 10:29:07 +02:00
Member
Copy Link

Changed status from 'Needs Triage' to: 'Archived'

Changed status from 'Needs Triage' to: 'Archived'
Ankit Meel self-assigned this 2020-04-20 10:29:07 +02:00
Ankit Meel commented 2020-04-20 10:29:07 +02:00
Member
Copy Link

Initial Velocity
When enabled, the fluid will inherit the momentum of the flow source.

So a stationary object will not give a velocity of 2 in any direction.
https://docs.blender.org/manual/en/latest/physics/fluid/type/flow.html#initial-velocity

> Initial Velocity > When enabled, the fluid will inherit the momentum of the flow source. So a stationary object will not give a velocity of 2 in any direction. https://docs.blender.org/manual/en/latest/physics/fluid/type/flow.html#initial-velocity
Richard Antalik commented 2020-04-20 13:19:29 +02:00
Member
Copy Link

Changed status from 'Archived' to: 'Confirmed'

Changed status from 'Archived' to: 'Confirmed'
Richard Antalik commented 2020-04-20 13:19:29 +02:00
Member
Copy Link

In #74818#913855, @ankitm wrote:

Initial Velocity
When enabled, the fluid will inherit the momentum of the flow source.

So a stationary object will not give a velocity of 2 in any direction.
https://docs.blender.org/manual/en/latest/physics/fluid/type/flow.html#initial-velocity

I will reopen and confirm because this doen't make sense - Setting Z initial velocity has effect on stationary source, but it is not specified in which coordinate space.

So I guess this is double wrong..

> In #74818#913855, @ankitm wrote: >> Initial Velocity >> When enabled, the fluid will inherit the momentum of the flow source. > So a stationary object will not give a velocity of 2 in any direction. > https://docs.blender.org/manual/en/latest/physics/fluid/type/flow.html#initial-velocity I will reopen and confirm because this doen't make sense - Setting Z initial velocity has effect on stationary source, but it is not specified in which coordinate space. So I guess this is double wrong..
Ankit Meel removed their assignment 2020-04-23 08:56:40 +02:00
Jacques Lucke commented 2020-05-12 13:52:32 +02:00
Member
Copy Link

Added subscriber: @JacquesLucke

Added subscriber: @JacquesLucke
Jacques Lucke commented 2020-05-12 13:52:32 +02:00
Member
Copy Link

The behavior seems to be the same in the old fluids system. Therefore, I think this is not a bug in Blender, but in the documentation (I'll fix that).

We might want to change the behavior at some point, but that is outside of the scope of a bug report.

The behavior seems to be the same in the old fluids system. Therefore, I think this is not a bug in Blender, but in the documentation (I'll fix that). We might want to change the behavior at some point, but that is outside of the scope of a bug report.
blender-admin commented 2020-05-12 13:55:58 +02:00
Copy Link

This issue was referenced by blender/blender@fffcb6e480

This issue was referenced by blender/blender@fffcb6e48068d77de6bbaaf35ef30515d1078dac
Jacques Lucke commented 2020-05-12 13:56:36 +02:00
Member
Copy Link

Changed status from 'Confirmed' to: 'Resolved'

Changed status from 'Confirmed' to: 'Resolved'
Jacques Lucke self-assigned this 2020-05-12 13:56:36 +02:00
blender-admin commented 2020-05-12 14:03:44 +02:00
Copy Link

This issue was referenced by 6651

This issue was referenced by 6651
Hmeliq commented 2021-09-20 14:02:41 +02:00
Copy Link

Added subscriber: @HmeliQ

Added subscriber: @HmeliQ
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels   
Meta
Good First Issue

  
Module
Animation & Rigging

  
Module
Core

  
Module
Development Management

  
Module
Eevee & Viewport

  
Module
Grease Pencil

  
Module
Modeling

  
Module
Nodes & Physics

  
Module
Pipeline, Assets & IO

  
Module
Platforms, Builds, Tests & Devices

  
Module
Python API

  
Module
Rendering & Cycles

  
Module
Sculpt, Paint & Texture

  
Module
User Interface

  
Module
VFX & Video

  
Priority
High

  
Priority
Low

  
Priority
Normal

  
Status
Archived

  
Status
Confirmed

  
Status
Duplicate

  
Status
Needs Information from Developers

  
Status
Needs Information from User

  
Status
Needs Triage

  
Status
Resolved

  
Type
Bug

  
Type
Design

  
Type
Known Issue

  
Type
Patch

  
Type
Report

  
Type
To Do

No Label
Meta
Good First Issue
Module
Animation & Rigging
Module
Core
Module
Development Management
Module
Eevee & Viewport
Module
Grease Pencil
Module
Modeling
Module
Nodes & Physics
Module
Pipeline, Assets & IO
Module
Platforms, Builds, Tests & Devices
Module
Python API
Module
Rendering & Cycles
Module
Sculpt, Paint & Texture
Module
User Interface
Module
VFX & Video
Priority
High
Priority
Low
Priority
Normal
Status
Archived
Status
Confirmed
Status
Duplicate
Status
Needs Information from Developers
Status
Needs Information from User
Status
Needs Triage
Status
Resolved
Type
Bug
Type
Design
Type
Known Issue
Type
Patch
Type
Report
Type
To Do
Milestone
Clear milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
No Assignees
Jacques Lucke
6 Participants
Notifications
Due Date
The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'.

No due date set.

Dependencies

No dependencies set.

Reference: blender/blender-manual#74818
No description provided.
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?