river polys

#1
What is the conventional wisdom on river polys? Say I have a few miles of snaking river, do I do it piece-wise? I seem to be crashing SBX alot when making these polygons and they do have ALOT of verticies.

If piece-wise is the way, Can the polygons overlap by a few pixles at the ends to join them or should I gap them by a bit?

Change in elevations... go a few hundred yards and drop the polygon altititude by a foot? After a few miles, the river is cut in deep up stream and ends on a plateau downstream. This is the apporach I am thinking of taking but am interested in any other words of wisdom.

EDIT

Also, I have been struggling with shore lines... heck, any lines. I can't find any (meaningful) information on how to use poly lies to create the smooth transition from my water poly to the land. I even tried just drawing a 4-lane over my airstrip to see of that worked... and no. Are they saved seperately and part of a higher scenery layer, what? Help!


Yet another edit....

So in FSX, unless we use the modified terrain.cfg we have only generic (that one works)... but if I use the mod file FTX-NA gets screwed up. Guess I'll have to find a solution for that...
 
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rhumbaflappy

Moderator
Staff member
Resource contributor
#2
Legacy_LWM_Water_NoFlatten is the 'tag' you would want for the water polys. Go ahead and overlap them... should make no difference.

Regarding shorelines, I think there is a Shorelines_Generic_River. The General tab of the line's Properties popup allos you to define the width. You might try 32 for a width, as you can change this later.

TMFViewer will show you if you have a valid BGL, even if it doesn't show in FSX for some reason.

You can use the Make L option with polys, then in Line Mode, you can use 'B' while selecting points to break the line at the point. Then you can delete any line portions that overlap the river, by deleting the points or dragging them to where they belong.

Dick
 
#3
Didnt use the legacy poly, used hydro generic river perinnial. Is there a reason I shouldn't?

There is NOTHING that I seem to be able to do to change the width of that shoreline set for 1 or 500... it stays the same.
 

Luis_Sá

Resource contributor
#4
Didnt use the legacy poly, used hydro generic river perinnial. Is there a reason I shouldn't?

There is NOTHING that I seem to be able to do to change the width of that shoreline set for 1 or 500... it stays the same.
Hello,

In FSX the width of lines can only be changed globally by editing the terrain.cfg. That was not the case in FS9. Therefore, in FSX, rivers of variable width can only be done with polys. Note that, in SBuilderX, you can "transform" (fat) lines into polys.

Kind Regards, Luis
 
#5
Partial success....

I edited a river piece wise, set elevations for each section and welded them together. My start elevation is 672 meters and flows down to 654. When I tested the poly in FSX, I was both pleased and peaved...

I was expecting that I would have 1 meter drops from time to time, what I got was a nice smooth slope poly that had no transitions from one elevation to the next (my rapids and waterfalls)...

So, success, I have a nice river that flows down hill, but failure too because I don't have my rapids and falls.

A few questions arise...

1) why did this happen?

2) Is there any ways to parse thru the points in the properties screen to set elevation or must I pick each point individually with the mouse?

3) I have this rather complicated river that I would like banks for, now... but I can't convert a poly to a line in order to create the shore line. Now what? Am I out of luck and will have to hand draw the line for the shore lines?

4) I can't apply smooth to the poly to make it pretty because every added point is at elevation 0, the poly turns into shark teeth. Any way around this?
 
#6
Hello

Some points concerning slopy hydro polygons; I used many in Madagascar FSX project.


Important: you need a good improved mesh, so your river draw from satellite views would be correct with FS valleys; with default mesh, you will probably waste your time!

Try first to draw a single line following river, tagged as a wide road (to be more visible), and check in FSX if it correctly follows the valley.
In slow mode, note elevation at several points; then you can analyse changes of slope (you can "note" provisionnaly your numbers or comments in SBX using blue lines).

Now you can split the different poly parts you need to create; in very sinuous areas (often nearly flat), better way is to create a flat poly, even if you have a small error.

Concerning poly draw, you can make poly from a line (eventually with continuous width change), but result will be too regular and needs to be reworked. Better (long job!) draw poly directly on GE background (I generally use zoom 14). Save project very regularly, because of unpredictable crash during this type of work!

About shorelines: better use generic shorelines tags; other tags are very various, but are rendered too large. Take care of orientation, eventually use reverse tag; I remind that water side (and waves) are righthand of line when running in increasing order of vertex numbers. Long job if you have many polys at junctions: you have to break lines and delete "end" segments; then adjust polys and lines...

To avoid changes, test project with polys only before adding shorelines.

About islands in rivers: use set as hole before applying slope so island have correct local elevation; if you add an island after this work, elevation is set to 0.

About WaterClass: sometimes, if you use ocean tag for mouths of river, it will be rendered too lagoon blue and you need to apply new WC to get more browny colour.

If your project seems too complex, take care to split before crash!

Some final details: maybe you'll have to delete default bridges if misplaced with your river; use an exclude box; then, rebuild a new extrusion bridge...
Default roads will probably be misplaced or cross your new river... great job, maybe endless!

Be patient: maybe better to create a provisionnal project, even imperfect, so you allready can fly with a rather good landscape, and then improve when you have time.

I don't say my way is the correct one; I just report it to share with interested persons. All remarks to improve are welcomed. Thanks.

Pierrot - FMEP


Answer to point 3 of former post: when you have your poly, with poly tool, use "Make line" item to create the line and keep your poly; then, line tool to work this line.
 
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Luis_Sá

Resource contributor
#7
Hello,

Hum ... very interesting. One thing that I wanted to make when FSX came about was to make rivers whose altitude decrease from the source to mouth ... but I had not the time to make scenery. May be a screen shot would be nice to illustrate your method.

One small note: there are 2 parameters that you can set in the INI file to make automatic savings of your work at predefined intervals. I don't remember the name of the backup file (but it will have the basis name of the working file).

These are the default values of the referred to parameters:

Code:
BackUpON=False
BackUpSeconds=60
Best Regards, Luis
 
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#8
Thanks for interest, and all your helps since some years!

Ok! a tuto would be useful, but I have no time presently, and my web connection is too slow for pics.
Particularly, choice of slope may cause problem for many people (definition is based on vertical gap (in meters or feet), and horizontal distance (in minutes of angles); a tool in slope window where we can type both info in meters and compute slope would be convenient (calculation depends on latitude of place).

I have a question concerning impact on frames, due to complex sceneries?

Other question: is it possible to "break" a poly (other way than split QMID)?
Presently my way is to transform poly to line, break line, convert back lines to poly.

Pierrot - FMEP
 
#9
Hello

Concerning automatic backup: my problem was due to the fact I open the myname file instead of myname_BAK file ; this one is the latest working version.

If I open the myname file, it is rapidly saved as a BAK file, and both are older version.

Now it works; I open the latest BAK file, and immediately save as myname.


Pierrot - FMEP
 
#10
Hello,

Hum ... very interesting. One thing that I wanted to make when FSX came about was to make rivers whose altitude decrease from the source to mouth ... but I had not the time to make scenery. May be a screen shot would be nice to illustrate your method.

Best Regards, Luis
I've been working on river polys recently. It started as a simple desire to display the river in my home town which Microsoft had omitted in FSX. Here's my method, which is pretty simple using SBuilderX.

Draw a poly for a segment of river, beginning and ending at a road, dam, lake or creek. Not too long, but 3-4 kilometers is ok though. Use the measure tool to get the distance and heading between the two extreme points. Assign an altitude to the lower point, then enter the heading and slope info to the furtherest point. Assign your water texture, and you're done. Check it in FSX to see if any of the water is higher than the surrounding mesh. I usually place my water about one or two meters below the actual elevation to get a nice depression. Another enhancement I like is to draw another land class poly of identical slope "below" the river segment to give the river a nice wooded or brushy bank appearance. A nice forest land class works for me. It also makes a shoreline less necessary. One more item. A sloped poly with a concrete texture makes a quick and easy dam.
 
#11
Those are some good tips. I will run a mouse over google earth to get elevations (if you use addon mesh it works pretty well). If the river is fairly narrow, and more or less constant width, I will create line down the center, set the line width to what I want the river to be, and convert to poly. Then I create a line from the poly, which creates the shoreline. If the river is sloping, I will cut the polys by setting the QMID level to one which gives the number of segments I want and slicing. Normally I just make each poly constant altitude, and if you stair-step by 1 or 2 meters you can't see it, unless the river is big enough that someone can get a float plane down to the surface. Note that you essentially have 3 FSX shorelines. The ocean one is 50m wide, and there are 10 and 5m inland shores. I find the 5m to be next to worthless. I pretty much use the 10m for everything.

scott s.
.
 
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#12
If the river is fairly narrow, and more or less constant width, I will create line down the center, set the line width to what I want the river to be, and convert to poly. Then I create a line from the poly, which creates the shoreline.
scott s.
.
Very interesting! Can you give a little elaboration on converting line to poly? It sounds like a time saver.
 
#13
In SBX just create your line, then select the line and right-click to get the context menu. One option is to set the width, set it to how wide you want the river. Once you set that right click to get the context menu again, and just select convert to poly. Basically you get each point of the line doubled and separated by the width. What I find is once you have converted to poly, you can select the poly and experiment with the "smooth" tool to add in more points. It tends (at least to me) to make it less obvious that both banks of the river are identical.I find it looks best if the river isn't too wide (30-70m or so). But I think it is better than trying to use a streamline for smaller rivers, which can be hard to see from the air.

scott s.
.
 
#14
Thanks, Scott! I'll give it a try.

EDIT: Works like a champ! Your method is faster, and it is still very easy to move a few of the vertices about to make the river width vary a bit. Thanks for the tip.
 
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