Virtual Litchi Mission

[ThorDar]

Download latest version here :
Virtual Litchi Mission V2.3.0
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VLM Frequently Asked Questions

Problems Getting Started

Q) VLM does not start properly – startup sound and splash screen and then nothing!
A) Restart VLM while pressing CTRL and you will be given the option to reset VLM to initial conditions

Q) The Litchi Mission Hub panel in VLM is shifted from its expected location?
A) Try running in compatibility mode by right clicking on the VLM icon and choose

Compatibility tab -> Change High DPI Settings -> High DPI Scaling Override.

Q) VLM runs but Google Earth does not open?
A) Check that Google Earth Pro is properly installed and that kml files are properly associated with Google Earth. You can check this by double clicking on a kml file and confirming that Google Earth opens.

Q) VLM crashes on startup complaining about 'CefSharp.Core.dll' or one of its dependencies.
A) Check that the following are properly installed on your system:
Microsoft Visual C++ 2015 Redistributable (x64)
Microsoft Visual C++ 2013 Redistributable (x64)
Microsoft .NET Framework 4.6

Q) Can I run VLM on a Mac?
A) VLM is a windows only application. You have two options to run on a Mac or Linux machine

1) Apparently VLM runs well in a Virtual Machine such as Parallels​

2) User Bazuchan has implemented a version of VLM which runs as an extension to the browser. Yet another Virtual Litchi Mission (Google Chrome Extension)​

Problems with the Virtual Mission

Q) The elevations of my virtual mission look wrong
A) Check the following:

1) The exaggeration factor in Google Earth should be set to 1.0​

2) Check that Litchi Mission Hub, VLM and GE are all using either Imperial or Metric units – do not mix them.​

3) Check that the VLM Home Point Reference Altitude is appropriate for your mission. If you are unsure then use the default setting of WP1 and put the first WP of your mission directly above the Home Point (Take Off Point)​

4) If there are still small elevation differences then compare the elevation of the Home Point in both Google Earth and Google Maps (ie Litchi). If they are significantly different then set the VLM HP altitude to the elevation measured by Google Earth.​

Q) The VLM Mission is a poor match with the real mission
A) Check the following:

1) Check that you have specified a heading and gimbal angle for every waypoint of your mission. If any of these values are undefined you will see an orange warning in the VLM Activity Log.​

2) Check that your mission does not exceed the capabilities of your drone. Any such issues will be highlighted in orange in the VLM Activity Log and should be addressed.​

3) Check that the Google Earth viewing window is set to 16:9 to match your camera settings.​

4) Check that the drone type is set correctly in VLM and that the FOV setting is correct.​

5) Check that the VLM Cruising speed matches the setting in the Litchi Mission Hub.​

6) If the VLM mission is jerky then try increasing the number of smoothing points to 9 or 11.​

If you still have questions or problems then please ask in this thread.
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Original post dated 26/12/2017:

In this thread started almost a year ago - https://mavicpilots.com/threads/how-hard-would-it-be-to-simulate-litchi-missions-in-google-earth.7864, user “torqum” introduced the intriguing idea ‘flying’ a Litchi mission virtually in Google Earth to see how it looks from the perspective specified in Litchi. It was a very appealing concept – to fly a mission anywhere in the world without getting out of your armchair!

In that thread, user "JTS" submitted a conversion program which apparently worked for some folks but not for others – and not for me so I decided to write my own.

The utility is called Virtual Litchi Mission (VLM) – it is a standalone executable and does not need any installation. It runs on my Win10 x64 machine but should run on x86 machines as well. On older versions of windows your mileage may vary…..

VLM sets a watch on a user specified Downloads folder and will automatically read any csv file created in this folder. When Litchi Mission Hub writes a csv file to this folder, VLM will convert it to a “Tour” in Google Earth including the complete camera orientation and gimbal settings which were specified in Litchi.

The resulting Virtual Mission can then be flown in Google Earth and should show results very similar to that obtained when the mission is flown with your drone. I have tried it out on quite a few of the public missions available in Litchi Mission Hub and in areas where the satellite imagery is good, the results are impressive. Google Earth is so amazing!!

I have found VLM useful to check that there are no erroneous parameters in my Litchi Mission and to check that the camera ‘sees’ what I want it to see. It has saved me several wasted flights with my mavic.

A full User Guide is available in VLM under the Help Tab

Please give VLM a try and let me have any feedback, comments etc. I hope you find it useful.

Thanks

N

Love VLM but it's broken right now. Are you going to be able to fix this problem or do we just wait or what's the scoop?

 

[Peio64270]

Hum, you guys saying that you already paying for the google API stuff, I never have, I will if I have to, but I think it related to @namirda program or web server, etc. Have no problem paying him for his stuff.

Until he gives us an update, I think more posts on this thread is waist of time.

Rod

About a problem I had recently with elevation data at some locations, Namirda was answering what follows :

"I am completely sure that VLM gets its elevation data from the Google API because I wrote it!

However I was not aware that Litchi have made a move away from Google due to their pricing changes. Fortunately, those pricing changes do not currently apply to VLM because it is not a commercial application and the number of API hits per day is below the minimum threshold. For now I can still get elevation data from Google for free - I hope that does not change." (Message #658 of this thread)

It looks like "that did change" and I am surprised not to get any message from Namirda about this issue. Maybe he could commercialize VLM and pay fees to Google ? I really don't know but I miss VLM a lot, presently...

 

[RodPad]

Thanks for pointing out that post, I hardly sign on to this forum. (haven't been following this).

Here is a trick to post a link to that specific post.
Right click the #658 / Copy link location.

Virtual Litchi Mission

Even if the drone is out of range of the controller, ie disconnected, it will still interpolate poi. It can not receive your "focus" command if it is disconnected but will still interpolate. Interpolate has nothing to do with the RC, it has to do with GPS and Litchi. Yeah - I get that it won't...

mavicpilots.com

Rod

 

[namirda]

Hi All,

I'm very sorry for the problems being encountered with VLM over recent days - and also for my tardy response.

I am normally informed by email when there are new posts on this thread but somehow that did not happen this time.

It seems that we have hit the limit of Google's generosity with our increasing use of their elevation API!!

When I wrote VLM I never thought for a minute that it would become as popular as it has ( there are now more than 3500 regular users !!) and so I hard wired my own API key into the program thinking that our combined usage would be well within the limits of Google free plan.

That worked for more than a year - but it seems no longer.

There are a few possible solutions - I will investigate these and report back shortly.

Neil

 

[Peio64270]

Hi All,

I'm very sorry for the problems being encountered with VLM over recent days - and also for my tardy response.

I am normally informed by email when there are new posts on this thread but somehow that did not happen this time.

It seems that we have hit the limit of Google's generosity with our increasing use of their elevation API!!

When I wrote VLM I never thought for a minute that it would become as popular as it has ( there are now more than 3500 regular users !!) and so I hard wired my own API key into the program thinking that our combined usage would be well within the limits of Google free plan.

That worked for more than a year - but it seems no longer.

There are a few possible solutions - I will investigate these and report back shortly.

Neil

Don't be sorry ! Your program is an amazing tool and we broadcasted an enthusiast publicity for it (I the first). So, this is our fault. We'd have rather kept it secret Now, if you have to pay for the Google's API, I think that almost all these 3500 users would be happy to participate...
Have a nice day.

 

[webvan]

Thanks for the update. Adding a setting so users can put their own key (easy enough to get if you have a gmail account) would likely be the quickest fix ?

 

[namirda]

After a little investigation, it appears that some time last year Google made significant changes to their charging model. They must have been slow in implementing the changes because it is only very recently that VLM has been affected.

The situation as I understand it is now as follows :

1) All API usage now requires an associated billing account complete with credit card details.
2) Each account is provided with $200 free usage per month.
3) The cost for using the Elevation API is $5 per 1000 hits - meaning that the first 40,000 hits per month are free

In the last 30 days, there were 32,948 hits from VLM to the Elevation API - meaning that we have almost reached the 40k limit beyond which we need to pay for our usage.

I have now created a billing account for VLM and so everything should now be working again - please let me know if you still have problems.

This is only a temporary solution - VLM is free software but Google APIs now have a subscription model and the two are incompatible. I will pay the bill for a month or two but clearly this is not sustainable.

Unless anybody has a better solution, I propose to do as @webvan suggests in the post above and make an update to VLM so that users can input their own API key. These are easy to obtain by opening an account with Google and it is free for small usage - unfortunately when we all use VLM on the same account it is no longer considered small!

Please let me know if you have any better suggestions.

Thanks

Neil

 

[Peio64270]

After a little investigation, it appears that some time last year Google made significant changes to their charging model. They must have been slow in implementing the changes because it is only very recently that VLM has been affected.

The situation as I understand it is now as follows :

1) All API usage now requires an associated billing account complete with credit card details.
2) Each account is provided with $200 free usage per month.
3) The cost for using the Elevation API is $5 per 1000 hits - meaning that the first 40,000 hits per month are free

In the last 30 days, there were 32,948 hits from VLM to the Elevation API - meaning that we have almost reached the 40k limit beyond which we need to pay for our usage.

I have now created a billing account for VLM and so everything should now be working again - please let me know if you still have problems.

This is only a temporary solution - VLM is free software but Google APIs now have a subscription model and the two are incompatible. I will pay the bill for a month or two but clearly this is not sustainable.

Unless anybody has a better solution, I propose to do as @webvan suggests in the post above and make an update to VLM so that users can input their own API key. These are easy to obtain by opening an account with Google and it is free for small usage - unfortunately when we all use VLM on the same account it is no longer considered small!

Please let me know if you have any better suggestions.

Thanks

Neil

Thank you so much, Namirda.
Indeed if you update your application I think that all of us will be happy to open a personal account at Google for this API.

 

[ThorDar]

It is indeed working again!!

Thank you so much!

 

[ThorDar]

Thank you so much, Namirda.
Indeed if you update your application I think that all of us will be happy to open a personal account at Google for this API.

Agreed.

 

[joeruby]

After a little investigation, it appears that some time last year Google made significant changes to their charging model. They must have been slow in implementing the changes because it is only very recently that VLM has been affected.

The situation as I understand it is now as follows :

1) All API usage now requires an associated billing account complete with credit card details.
2) Each account is provided with $200 free usage per month.
3) The cost for using the Elevation API is $5 per 1000 hits - meaning that the first 40,000 hits per month are free

In the last 30 days, there were 32,948 hits from VLM to the Elevation API - meaning that we have almost reached the 40k limit beyond which we need to pay for our usage.

I have now created a billing account for VLM and so everything should now be working again - please let me know if you still have problems.

This is only a temporary solution - VLM is free software but Google APIs now have a subscription model and the two are incompatible. I will pay the bill for a month or two but clearly this is not sustainable.

Unless anybody has a better solution, I propose to do as @webvan suggests in the post above and make an update to VLM so that users can input their own API key. These are easy to obtain by opening an account with Google and it is free for small usage - unfortunately when we all use VLM on the same account it is no longer considered small!

Please let me know if you have any better suggestions.

Thanks

Neil

Yes I would appreciate the ability to use my own API key for VLM. This will take the cost load off of you.
You have created a very useful program VLM. I have been using it every day. I panic when it went down - ha ha.
I think I have found a problem with the VLM simulation and have been communicating with Bazuchan with GCE Google Chrome Extension - which uses your VLM techniques. I think the problem is in both. I wanted to link this info to you here.

See: post 101 and 113, 114 at:

Yet another Virtual Litchi Mission (Chrome/Firefox Extension)

Hi Bazuchan, I think I found a bug in GCE. I also think it was there in VLM too. I have been trying to find what I did wrong, but can't. Here is the problem I see: When flying between two waypoints with curved turns, the camera (in the simulation) turns well before the curved section of flight...

mavicpilots.com

!!!!!!!!!!!!!!!!!!!!!!
Yes that is what I am seeing. The simulation AC Yaw starts turning immediately after start, instead of waiting for the AC to get to the curved portion which is about 0.4 miles away. My actual flight video shows that the AC Yaw angle stays constant until about the 0.4 mile point then it starts changing to the new waypoint direction. Thus the simulation and the actual flight don't match. I hope I am making sense.
!!!!!!!!!!!!!!!!!!!!!!

 

[namirda]

Yes I would appreciate the ability to use my own API key for VLM. This will take the cost load off of you.
You have created a very useful program VLM. I have been using it every day. I panic when it went down - ha ha.
I think I have found a problem with the VLM simulation and have been communicating with Bazuchan with GCE Google Chrome Extension - which uses your VLM techniques. I think the problem is in both. I wanted to link this info to you here.

See: post 101 and 113, 114 at:

Yet another Virtual Litchi Mission (Chrome/Firefox Extension)

Hi Bazuchan, I think I found a bug in GCE. I also think it was there in VLM too. I have been trying to find what I did wrong, but can't. Here is the problem I see: When flying between two waypoints with curved turns, the camera (in the simulation) turns well before the curved section of flight...

mavicpilots.com

!!!!!!!!!!!!!!!!!!!!!!
Yes that is what I am seeing. The simulation AC Yaw starts turning immediately after start, instead of waiting for the AC to get to the curved portion which is about 0.4 miles away. My actual flight video shows that the AC Yaw angle stays constant until about the 0.4 mile point then it starts changing to the new waypoint direction. Thus the simulation and the actual flight don't match. I hope I am making sense.
!!!!!!!!!!!!!!!!!!!!!!

Hi,

I have taken a quick look at your mission. As you say, VLM starts to yaw immediately after start - because that is what I think Litchi is doing - or at least it is what they say they are doing!

If you look in the Litchi documentation you will find the following :

"
Heading: The direction relative to north in which the aircraft will look at when arriving at this waypoint (0° is North, 90° is East). This setting only applies when the mission setting "Heading Mode" is set to "Waypoint Defined" ("Custom" on iOS). If two consecutive waypoints have different headings, the aircraft will smoothly transition from one heading to the other while travelling from the first waypoint to the second.
Info The waypoint heading is represented by the blue aircraft icon on top of each waypoint. It will update dynamically as you adjust the heading setting.

"
Now maybe this information from Litchi is wrong or outdated? Perhaps you could ask them and let us know?

N

 

[AMann]

After a little investigation, it appears that some time last year Google made significant changes to their charging model. They must have been slow in implementing the changes because it is only very recently that VLM has been affected.

The situation as I understand it is now as follows :

1) All API usage now requires an associated billing account complete with credit card details.
2) Each account is provided with $200 free usage per month.
3) The cost for using the Elevation API is $5 per 1000 hits - meaning that the first 40,000 hits per month are free

In the last 30 days, there were 32,948 hits from VLM to the Elevation API - meaning that we have almost reached the 40k limit beyond which we need to pay for our usage.

I have now created a billing account for VLM and so everything should now be working again - please let me know if you still have problems.

This is only a temporary solution - VLM is free software but Google APIs now have a subscription model and the two are incompatible. I will pay the bill for a month or two but clearly this is not sustainable.

Unless anybody has a better solution, I propose to do as @webvan suggests in the post above and make an update to VLM so that users can input their own API key. These are easy to obtain by opening an account with Google and it is free for small usage - unfortunately when we all use VLM on the same account it is no longer considered small!

Please let me know if you have any better suggestions.

Thanks

Neil

Hey Namiranda,

I know you didn’t ask for this and might not want to accept it, however do you have a PayPal email account for donations? Many of us would really appreciate being able to put a little bit in the jar to help out. As I don’t live in New Zealand, it’s the only way I can buy you a cold one to say thanks!

-Anthony

 

[namirda]

Hey Namiranda,

I know you didn’t ask for this and might not want to accept it, however do you have a PayPal email account for donations? Many of us would really appreciate being able to put a little bit in the jar to help out.

Thanks!!!

-Anthony

Thanks Anthony - but really not necessary. I prefer to keep this a little hobby rather than make it seem like paid work!

I will shortly put up a new version of VLM where you will be able to use your own API key rather than use mine!

Thanks again.

N

 

[AMann]

Thanks Anthony - but really not necessary. I prefer to keep this a little hobby rather than make it seem like paid work!

I will shortly put up a new version of VLM where you will be able to use your own API key rather than use mine!

Thanks again.

N

OK, but I still owe you a cold one!

 

[joeruby]

Hi,

I have taken a quick look at your mission. As you say, VLM starts to yaw immediately after start - because that is what I think Litchi is doing - or at least it is what they say they are doing!

If you look in the Litchi documentation you will find the following :

"
Heading: The direction relative to north in which the aircraft will look at when arriving at this waypoint (0° is North, 90° is East). This setting only applies when the mission setting "Heading Mode" is set to "Waypoint Defined" ("Custom" on iOS). If two consecutive waypoints have different headings, the aircraft will smoothly transition from one heading to the other while travelling from the first waypoint to the second.
Info The waypoint heading is represented by the blue aircraft icon on top of each waypoint. It will update dynamically as you adjust the heading setting.

"
Now maybe this information from Litchi is wrong or outdated? Perhaps you could ask them and let us know?

N

Yes, I will ask Litchi, and get back with you.

However, when the aircraft actually fly's the mission using the Litchi app, the aircraft fly's straight most of the way to the next waypoint, and then, depending on the curve size I set, it follows the blue path and starts the turn smoothly to the next heading. The simulation is not doing that. Maybe the Litchi group can help answer that. I will get back when I get a response from Litchi. Thanks a lot for your VLM and your help.
Joe
KC7GHT

 

[RodPad]

Thanks Anthony - but really not necessary. I prefer to keep this a little hobby rather than make it seem like paid work!

I will shortly put up a new version of VLM where you will be able to use your own API key rather than use mine!

Thanks again.

N

Hello,

I would prefer to pay money to you, instead of google.

"a little hobby rather than make it seem like paid work!"

But, well..
Yes, I know what your talking about.


Rod

 

[joeruby]

Hi,

I have taken a quick look at your mission. As you say, VLM starts to yaw immediately after start - because that is what I think Litchi is doing - or at least it is what they say they are doing!

If you look in the Litchi documentation you will find the following :

"
Heading: The direction relative to north in which the aircraft will look at when arriving at this waypoint (0° is North, 90° is East). This setting only applies when the mission setting "Heading Mode" is set to "Waypoint Defined" ("Custom" on iOS). If two consecutive waypoints have different headings, the aircraft will smoothly transition from one heading to the other while travelling from the first waypoint to the second.
Info The waypoint heading is represented by the blue aircraft icon on top of each waypoint. It will update dynamically as you adjust the heading setting.

"
Now maybe this information from Litchi is wrong or outdated? Perhaps you could ask them and let us know?

N

Namirda here is what I just emailed to Litchi. Thanks again for all of your effort and help.
Joe
KC7GHT
~~~~~~~~~~~~~~~~~~~~~~~~~
Gentlemen,

I have been using some software developed by Mr. Namirda called Virtual Litchi Mission (VLM). It purpose is to simulate a Litchi waypoint mission and fly the mission in Google Earth simulating not only the 3 dimensional flight path, but also the camera angles and camera field of view. It is a very useful program in planing my Litchi missions. A lot of DJI pilots, like myself flying a P3P, are using it.

I have discovered a problem with the simulation. More accurately, a lack of simulation of when to start rotating the Camera (which is connected to the aircraft (AC) body), when flying a curved turn. In the present simulation, the AC follows the desired mission path lat/long properly (blue path). However, in the simulation, the camera/AC start turning immediately instead of waiting until AC arrives at the start of the curve in the blue Lat/Long path.

Can you help Mr. Namirda obtain the information (data) from your Mission Hub CSV output necessary for him to determine when to start the camera turn so that the camera follows the blue path. In the simulation the AC follows the blue path correctly, but the camera turn does not. Any information you can provide would help.

For more info see the link below, and please see Post # 711, 712, and 716.

Virtual Litchi Mission

Thanks you so much for you help and suggestions.

Joe Ruby
KC7GHT

 

[joeruby]

Namirda,
Here is Litchi response below. I don't think they understood my question. My mission is Auto/TNW (auto toward next waypoint). Note that when I actually fly my mission, the aircraft and thus the camera fly correctly and turn when the flight path turns. I don't know how they do that in the Litchi App, and what they actually upload to my AC P3P, but the AC does fly the mission and the camera turns when the flight path turns (which is almost to the second waypoint).

I am really over my head in the programming of this. I don't know if the information you need to turn the camera/AC is available from Mission Hub, but yet you are able to fly the correct path in your simulation.

I can't help anymore than that. Thanks so much again for the VLM. It does so much for us the way it is.

Joe
KC7GHT

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Your request (204) has been updated. To add additional comments, reply to this email.

Litchi Support (VC Technology Ltd) 6 Jun, 17:48 BST Hello, I am not sure to understand the problem, which heading mode are you using? If you are using Auto/TNW, then the drone (and camera) will point forward in the direction of the mission path at all times. If you are using Custom/Waypoint Defined, then the drone (and camera) will rotate from the previous heading to the next heading between consecutive waypoints. Kind Regards, Litchi Online help at Help - Litchi

VC Tech 6 Jun, 16:55 BST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

[DJ Wes]

However, when the aircraft actually fly's the mission using the Litchi app, the aircraft fly's straight most of the way to the next waypoint, and then, depending on the curve size I set, it follows the blue path and starts the turn smoothly to the next heading. The simulation is not doing that. Maybe the Litchi group can help answer that. I will get back when I get a response from Litchi. Thanks a lot for your VLM and your help.
Joe
KC7GHT

Hi Joe etal,

I found your comments about aircraft heading versus VLM heading interesting. I have used Litchi for well over two years and I had always experienced that the heading of the aircraft between two waypoints interpolated smoothly between the heading specified at one waypoint to the heading specified for the following waypoint.

I just performed a little test. I flew two missions. Both had the exact same waypoints with the same exact headings. For the first mission I used “TNW” (to next waypoint) as the Heading Mode. For the second mission I used “Custom” (manually setting the heading to point at the next waypoint). When I flew these two missions I saw a different behavior in the heading mode of the drone. In the “Custom” mode, the drone smoothly transitioned from the heading defined at one waypoint to the heading defined at the next waypoint. However, in “TNW” mode, the heading of the drone was always tangent to its flight path. In other words, the drone always pointed forward along the path it was travelling.

I was surprised at this, but in my 2+ years of using Litchi, 90% of my missions used “Custom” waypoint headings (either POI or manually set). I may have only casually tried TNW without really looking closely at the heading of the drone. Therefore, my experience had been that the drone heading always smoothly interpolated between what was defined at each waypoint. Now, I know that the “Heading Mode” changes this behavior.

Namirda can comment on VLM’s implementation, but my experience with VLM suggests that it always has the aircraft heading interpolate smoothly between two waypoints, even when the “Heading Mode” is set to “TNW”.