Quick River Tool usage guide:
**Auto Line Traced River:
- Place new River BP tool:
I Placed it in GDC_Landscape_01 sublevel X2_Y1 at position 131240.0, -189420.0, -113230.0.
Upon default placement you should see this:
Note that I placed this inside of an erosion line that was formed by worldmachine. That is a good way to get a nice long river path. This mode only really works on landscapes that have terrains that are naturally eroded, otherwise you either need to define the points manually or carve out a flat and/or downhill path for the river.
Change “Sweep Radius” to 3500, “Checks per 360degrees” to 64 and “Steps” to 25:
Check "Draw Splines:
This is just the default box mesh.
Change RiverMesh to this asset (if you are using kite demo):
- Notice at first the river will be way too big and underground. We fix by changing “SplineScale” and “Z Offset”
- Now we want to flatten the landscape.
**Before you do, check the “SAVE” box! Otherwise your BP will trace down into its own channel and it will mess it up.
- Now we need to define some settings for our landscape flattening. Try these but they should be self explanatory:
Note that there is NO UNDO support for this. I suggest copying your BP to notepad and saving your level before proceeding. Also, use smaller settings for your width and falloff at first since you can increase the setting and run the flatten again, but you cannot make the channel smaller. Kind of like wood working, you can always take off but you can’t really add back on.
I actually gradually increased “channel falloff” to 300 to get the result in my next images. At that setting the landscape bank and river bank matched up perfectly. That is why you want to try and ‘sneak up’ on the right values rather than overshoot.
- This is when things get buggy right now. Open the BP editor and check and uncheck this box for both Spline components:
After doing that you should see both splines in the world, one will be a bit under the terrain because of the channel subtraction value.
- Now all that is left is to run the Flatten and Subtract Blutilities:
If you are lucky you will get something like this:
If I am being picky, the falloff is a tad harsh and the flat zone maybe a bit too wide. If I felt like re-loading the level and starting over maybe I’d tweak that… or if one day this supports undo.
Also note that you have to go into the EventGraph and change the landscape layer to paint if you want it to paint a layer like here (its painting rocks).
Currently it will not let you do anything custom to meet up with other rivers, but you can add manual points by adding to the “River Points” array and then position the end of the river exactly or add as many custom segments as you want. Note that when you add a new point it will go at local 0,0,0 which will be at the actor position (so the top of this river).
Here I added a manual point and dragged it down to the end showing how you could in theory make a nice transition piece and make your river meet up with it:
This is actually the first time I really took the time to try to use this tool. At the end we were so focused on polishing the cinematic and bug fixing that we really didn’t have time to go around and really add custom features to the landscape like we originally wanted.
**Now for manual mode. **
I suggest just using the checkbox “Save” whenever doing manual mode and just using RiverPoints array for simplicity. You don’t need to use the debug mode.
I am just going to press “clear” on the RiverPoints array from the above BP state.
Then after adding 1 item to the array, it shows up here at the actor position:
You need to select it and move it away from the origin every time you add a point otherwise they will all stack up and you will lose their order. Alternatively, you can duplicate the last item in the array just remember to move them out in order.
You will not see anything until there are at least 4 points. After that every new point adds a new segment:
If your river hits an absolutely flat spot, currently that will cause the line checks to fail to find the next lowest point. You can work around that by adding some value to the “Flow Height Bias”. It is just designed to help the river make it over a brief flat spot but it won’t work over long flats. That setting is a bit experimental and anything but very small values will break the lowest point algorithm. That is one of the things I’d like to improve some day.