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Glider accessories

Hi Ollie:

FYI: I am making a "quick-and-dirty" 3D model of the hangar in question from Trimble imagery in Sketchup to inquire into the 'scale' issue.

I will post some results on that in a while, in this same thread. :)



Oh wow, thanks a lot! I have been planning to create some 3D models but got no idea how to.

Is Sketchup free?

If so is there a tutorial?

Hi again:

Sketchup version 8 (32-bit) is available for use ...FREE. :wizard:

The updated URL for Sketchup version 8 (32-bit) to download direct from Trimble is here: ;)


FYI: Sketchup version-8 (32-bit) is the last version allowed to be used for both freeware and commercial purposes without a license and/or making a declaration of intended non-commercial use.

The original version-8 package is the 'fastest' working build compared to newer "Make" or 2013 / 2014 / 2015 / 2016 / 2017 / 2018 and/or 64-bit versions, and can be downloaded here:


BTW: AFAIK, that is the last issued and most current updated Sketchup version 8 released:


NOTE: Sketchup version-8 can run on Windows-XP if desired, although some (optional) plugin Ruby scripts may use DLLs that require more recent Windows component functions, and some dialog GUIs may require newer versions of Internet Explorer.

PS: AFAIK, Trimble discontinued Geolocation after May 2017 in all but the latest payware versions of Sketchup. :alert:


More links to info I posted on how to set up Sketchup will follow soon. ;)

Hope this helps get you started ! :)

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Hi Ollie:

First, see my edits above:


As I must depart for the evening ASAP, I had only a few moments to find and post some links here on Sketchup info that merit initial review:




More links to Sketchup setup info and tips to follow (...tomorrow ?). :)

Have fun ! :cool:

Thanks, Gary, here is what I have got so far :D

This is a glider trailer!
Screenshot (72).png

Going to tweak some details and add textures tomorrow if possible :D

Night, Ollie.
Hi Gary,

I'm trying to make the tail at the back curve, like the picture, but I don't know how to. Any ideas?

Screenshot (73).png
Hi Ollie:

The 'shorter' answer:

Use Push-Pull Tool to pull (aka "Extrude") the 'Selected' front Face of the vertical tail stabilizer forward to a point that the curve starts its ascent up and to the rear ...off of the top of the trailer body.

Use Tape Measure Tool to draw Construction Lines (aka "C-Lines" or "Guide" lines) ...on a side Face to create End Points.

< Guides are your friends; invite them into your project as often as needed ! >

Guides can then be Selected individually and Deleted, or they can all be Erased "when the party's over" via:

Sketchup Menu > Edit > Delete Guides :wave::laughing:

Place anchor points of Arc Tool between those Guide lines to draw a base line; pull out on mid-base line to form a curve with Arc Tool.

After the Arc is drawn, Select with the Pointer Tool, and push the Face fully across the vertical tail stabilizer to the back side Face extent, to a point such that the Face for the (no longer needed) outside portion of the curve 'deletes itself'.

I should have a 3D model of this object to post as an example illustration shortly. :)

I can also post some additional ideas for how to further enhance this 3D object if you like. :idea:

BTW: If you have not seen it yet, there is an abundance of excellent photos and 3-view (Top / Side / End) line diagrams which could be useful in making a precise model of the Cobra glider trailer(s) on the manufacturer website: :pushpin:



FYI: The 3-view images of ex: DoSi Class Cobra glider trailer can be imported as a Texture, and mapped as a Material onto selected Faces of a rectangular block 3D object "primitive" made with these dimensions:

10680 mm Long x 2180 mm High x 2050mm Wide

You may note that although the 3-view line diagrams are 'fairly' accurate, they are not precise vertically as to Tail height in the side view, and are also not accurate as to Tail center, Tail height, and Tail width in the Rear view of that trailer; re-size / position as necessary. :alert:

When the above Texture image Material is mapped onto ex: the front side, Select that Face, Right-click, and choose Texture > Position

* Click and Drag the Red Pin to Anchor the Bottom Left corner of the Material at the Bottom Left corner of the Face

* Click and Drag the Green Pin to set a position for the Bottom Right corner of the Material at the Bottom Left corner of the Face

NOTE: If necessary, pull up or down on the Green Pin to rotate axes / size a mapped Material to align an image along a Face Edges

* Click and Drag the Blue Pin to set a position for the Top Left corner of the Material at / near the Top Left corner of the Face

NOTE: If necessary, pull up or down on the Blue Pin to tilt axes /size a mapped Material to align an image along Face Edges

* Click and Drag the Yellow Pin to set a position for the Top Right corner of the Material at the Top Right corner of the Face

When the mapped Texture Material is properly positioned / sized / axially aligned with the Face, right-click and choose Done

BTW: Depending on how much detail you wish to put into this first 3D model, and whether it will be a significant visual asset that user aircraft will be able to see up close in FS, you may wish to add some more details to enhance realism.

CAVEAT: One must always keep in mind that one has a finite "budget" of system resources and rendering requirements that can be accommodated in a local scenery Area by the Windows FS task session's User Virtual Address Space (aka "USERVA"), and by the FS run time rendering engine sub-system.

So, we must choose carefully where and how we allocate parts of our "FS budget" to render scenery / aircraft / gauge info in detail. :teacher:

P3Dv4.x can use 64-Bit MDLs for 3D objects under DirectX-10 and DirectX-11 now, which makes more 3D model and scenery detail possible, so feel free to try out a very detailed model, especially if you may enjoy examining it up close at run time in P3Dv4. ;)

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Hi Gary,

I have followed your instructions, still needs improving but here is the tail part
Screenshot (74).png
That looks like it would work. :)

IIUC, the tail part is temporarily being modeled somewhere in front (or more precisely, off to the side in 3D space) ...of the trailer body.

When finished, you can Select all the portions (Edges and Faces) of the tail part, then right-click and Make Group.

Use the Move Tool to position that Group into alignment on top of the trailer body, then right-click and choose Explode (explode Group)

NOTE: Exploding that Group will result in the tail part Edges merging with- (aka "Welding" onto-) ...directly contiguous trailer Edges

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Hi Gary, slight issue here, I can't get this face to create. I'm trying to create a face fromany ideas on how to fix?
Screenshot (77).png

Thanks, Ollie.
HI Ollie:

Progress also has a way of teaching us new quirks encountered in- / required by- ...the 3D modeling process. ;)

The light gray-blue Face color indicates that a surface is 'Reversed'.

Select any / all such 'Reversed' Faces, Right-click on them, and choose "Reverse Faces".

Once all Faces are White on the outside surface of a 3D model, you will be more likely to properly form and/or Combine Faces, as well as to have any mapped texture Materials show up properly in FS at run time.

Regarding the creation of the Face on the Top Right side (viewed from the front end by the hatch door):

The Top-most surface has a diagonal line, but is not a required part of the trailer exterior surfaces ? :scratchch

If so, these can occur when a Face gets formed in a 'non-coplanar' alignment ...relative to adjacent Faces.

With all exterior Faces White, you should be able to select / Erase that- and all other- such diagonal lines that divide the trailer exterior surfaces

If instead such diagonal lines that divide the trailer exterior surfaces actually are required parts of the trailer, you may need to first draw a similar diagonal Edge line to form a Face from the front end of the 'intended' Top-Right Face, and joining at the rear-most End Point of the diagonal line on the right Edge of the Top-most Face of the trailer.

Then you should be able to form a Face on the remaining rear end of the 'intended' Top-Right side of the trailer.

Obviously, it is difficult both to describe- and follow- this process in written form; so feel free to ZIP and attach copy of the *.SKP project file either in this same public thread.

Alternatively, attach that ZIP file to a new 'Private Conversation' (aka "Private Message" or "PM") addressed to me here at FS Developer forum.

Either way, I'll check it out, and then I'll attach a ZIP file containing a 'fixed' copy for you to examine and do with as you wish. :)

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Hi Gary,

I have attempted to make some of the faces using the reverse face 'fix', this works for some parts, but not others.

Also, what does this mean 'non-coplanar' alignment ...relative to adjacent Faces' :D

Please don't spend all day working on it, I don't want you to feel pressured to do anything for me. But, here you go and thank you. :)

thanks, Ollie.


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Hi Ollie:

I am examining your attached 3D Model to see if there may be a reasonably easy way to repair some of the Face creation issues related to numerous asymmetries within the top surfaces of the trailer.

Apparently the base portion has good symmetry, but it seems the top surfaces of the trailer may have been drawn "freestyle" rather than by extruding an 'extension' (whether "Grouped" separate from the trailer base ...or not) off of the flat top surface of the trailer base portion, thereby creating a "block primitive" to be pared down into the desired shape.

One could otherwise modify that "block primitive" with the assistance of Guide lines etc. to ensure symmetry and alignment to the local 3D Axes of the trailer base itself.

I'll have another report- or 'fixed' version- to post sometime later (don't worry, I won't spend all day on this).

But since your day starts earlier than mine, do bear in mind that your time zone is about 5 Hours ahead of mine here in Chicago area on a Sunday morning, so it certainly might seem like a longer time to await a reply, as your day is already farther along than mine. ;)

That reminds me of a courtroom joke popular with some of my colleagues, wherein a Judge says to the person facing him at the bench:

"Have you ever been up before me ?"

The person facing him replies:

"I'm not certain, your honor; ...what time do you get up in the morning ?" :rotfl:

PS: Coplanar means "in the same exact flat plane of 3D space".

But in this case we are working with some non-square planes relative to the 3D modeling axes, so probably it might not be so much of an issue, as the asymmetries and positioning of Edge Lines and their End Points off of the vertical and horizontal axes of the 3D model in the top portion of the trailer which we must fix.

Reply to follow sometime reasonably soon (pending further copious infusions of caffeine). :)

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"Have you ever been up before me ?"

The person facing him replies:

"I'm not certain, your honor; ...what time to you get up in the morning ?"
Nice joke ;)

Apparently the base portion has good symmetry, but it seems the top surfaces of the trailer may have been drawn "freestyle" rather than by extruding an 'extension' (whether "Grouped" separate from the trailer base ...or not) off of the flat top surface of the trailer base portion, thereby creating a "block primitive" to be pared down into the desired shape

Ok, so the best option is to redesign the top so the lines are symmetrical, then the faces would connect.
I watched this video
. This helped me understand faces :D

Thanks, Ollie.
Indeed, that is yet another excellent example by Aidan Chopra which illustrates one of the "gotchas" we might encounter in 3D modeling. :)

Hi Gary,

Managed to simply the model a LOT using the 'tape measure tool'. This was VERY handy. Still, though this one face connecting two triangles will not connect unless I 'split' the shape in two. This will work, just annoying when I will texture it.
Screenshot (78).png

Shape 'split' in two.
Screenshot (79).png

Ollie :)
Hi Ollie:

'Fixing' the asymmetries and sizing issues ultimately compels re-modeling more than 1/2 of the original 3D model attached above. :oops:

Rather than keep you waiting much longer, I thought it best to initially attach a modified version of your original above, to illustrate the approach I am proposing, to make a glider trailer based on one which might be used for ex: the Southdown Gliding Club's Schleicher ASK 21 as derived from 3-view images mapped as Materials at real world scale ...onto a 'primitive' 3D model of the intended trailer.

Source: http://www.soarccsc.com/wp-content/uploads/2015/09/Schleicher-ASK-21-Flight-Manual.pdf


I have also attempted to illustrate an example of glider wing stowage positioning as well.


If that were to be a practical glider model that you might wish to create, (rather than another model you may be more personally familiar with which also uses a ex: Cobra trailer), perhaps exploring this very rough test of concept might prove helpful to the learning process ? :idea:

As I must attend to some other matters this Sunday, and can only get time free to work towards a more appropriate prototype intermittently today, I hope this may be of some initial use to the learning process. ;)

Please let me know if there was another type of glider that you had in mind for this trailer, and I will try to find some 3-view diagrams.

I anticipate that I may then be able to allocate more time to render a much better conceptual prototype in Sketchup tomorrow (Monday).

But I hope this first 'Q+D' 3D model still helps with the learning process; for all of us, that always involves an abundance of trial-and-error. :)

PS: To see the largely intact original of the top portion of the trailer encasement relative to the now uniformly proportioned trailer base:

...You may wish to view the Sketchup version-8 *.SKP file inside the attached ZIP ...within Sketchup version-8 using this option:

Sketchup Menu > View > Edge Style > check:

* Edges

Sketchup Menu > View > Edge Style > un-check:

* Back Edges


Sketchup Menu > View > Face Style > check:

* X-Ray View

* Shaded with Textures

After a new prototype is adapted from this first 3D model using 3-views for the intended glider trailer type, one can then replace the 3-view images mapped as Materials at real world scale, with texture images of a real world trailer scaled to fit the 3D model surfaces.

AFAIK, we should be able to "project" pre-sized trailer textures onto a (fully 'exploded') trailer as a whole in as little as 4 steps if all goes well.



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Wow, thanks Gary, very useful :D

So will I redesign the trailer based on the K21 three side view?

"project" pre-sized trailer textures onto a (fully 'exploded') trailer as a whole in as little as 4 steps if all goes well.

Thanks, Ollie.
Hi Ollie:

I would suggest that you instead consider using Cobra 2-Seater Trailer 3-view images to 3D model the trailer itself:


The Schleicher ASK 21 3-side view images may be more useful later, to verify horizontal / vertical clearance for fuselage, wings, and horizontal stabilizer stowage within the trailer top portion to ensure proper encasemnt of the aircraft. ;)

BTW: After researching this, apparently most such glider trailers are 'custom'; but IIUC, there are a (very few) pre-fabricated sizes from Cobra and others.

I found this ASK-21 glider trailer image to help with trailer size relative to glider fuselage positioning:


...and on-axis views to create a rear Face with a mid-line for symmetric break-lines between Arcs during 3D modeling:



More info forthcoming later... :)



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