Every mapper comes across errors, some are easy to solve and some are hard to find solutions for.

As I always do when finding out some solutions to ones that are hard to find, I write them down. 

Maybe the google or other search bots will pick up these and lead you here.

INDEX

Section	Description
1.	qhull precision error: (nodraw texture on a displacement)
2.	qhull precision error: (Badly made displacements)
3.	Day Of Defeat:Source Ladders. How to avoid issues.

qhull precision error: (nodraw texture on a displacement)

The full error I got was this...

qhull precision error: Only 4 facets remain. Can not merge another
pair. The convexity constraints may be too strong. Reduce the
magnitude of 'Cn' or increase the magnitude of 'An'. For example,
try 'C-0.001' instead of 'C-0.1' or 'A-0.999' instead of 'A-0.9'.

I got 17 OF them WITH THAT CONFUSING ERROR.

This error can have many reasons why it occurs, the message will not give you a location or a hint of where to look.

A hint from the hammer log was this...

Finding displacement neighbors...
Finding lightmap sample positions...
Displacement Alpha : 0...1...2...3...4...5...6...7...8...9...10
Building Physics collision data...

The errors are after a displacement build.

But how to find them is VERY hard and there isn't a lot written about it.

In this case I found the errors by systematically selecting only parts of the map, then using Run Map see if the errors occur and count how many there are in certain areas, making the areas smaller and smaller.  

Enter the Cordon Tool.

This will solve your issue. In my case it was in two locations of the map.

The cordon tool if used correctly you can select a smaller section of the map and compile just that area, it takes a while but you can eventfully rule out certain areas as the error doesn't occur in the log after "Run Map" is completed, where some areas it does.

1. Use the "Toggle cordon state" Button
2. Then Use the "Edit Cordon Bounds" Button to surround a small area.

Edit Cordon Bounds - making a cube around the area

3. Now with the map in that state, select "Run Map" to compile.
4. Considering I had 17 errors for the entire map in this case I got 6 in this one area.
5. I then reduced the cordon cube bit by bit until only one section remained...

Found the displacement error

6. The error in this case? I had a No Draw texture selected AND when I made one of the two blocks the power of the displacement was different
7. The fix was simple, use the "Toggle texture application" tool, "Displacement" tab and select "destroy" button.

From there you can now remake the displacement.

8. The other 11 errors were eventually tracked down to another area, with similar issues, destroying the displacement fixed all my errors. 

You will know when the errors are gone as you will get this in the log...

Finding lightmap sample positions...
Displacement Alpha : 0...1...2...3...4...5...6...7...8...9...10

...and no errors after that.

If that didn't work, hold on as there is another reason... or a few.

 

qhull precision error: (Badly made displacements)

As above this error will occur early on in the compile and it's to do with displacements.

Finding displacement neighbors...
Finding lightmap sample positions...
Displacement Alpha : 0...1...2...3...4...5...6...7...8...9...10
Building Physics collision data...

qhull precision error: Only 4 facets remain. Can not merge another
pair. The convexity constraints may be too strong. Reduce the
magnitude of 'Cn' or increase the magnitude of 'An'. For example,
try 'C-0.001' instead of 'C-0.1' or 'A-0.999' instead of 'A-0.9'.

Like above they all look the same, no clue of where that issue is, the above technique didn't work in a map I was trying to repair.

The map is called dod_hillside_1944. A remake of dod_hillside by a unknown author. This map ran like a absolute pig, very low FPS and also it had other issues that crashed RCBot2 waypoints.

It turns out there were SO MANY displacement errors repairing these is not viable. For a start some of the world geometry that made the displacements were not snapped to the grid or joined to each other, they were thin sheets of 1 unit.

Some were small vertical blocks simulating a bank on the side of the road. In one case the mapper made a round barn roof. now that is OK but it was made with 1 unit slabs, a set for the inside texture and another for the roof, another for the sides of the roof and another for the top...it was a unholy mess.

Worse, was every panel of the ground area was a mixed up set of thin sizes, different powers and overlapping not snapped to the grid, sharp vertical peaks.

So bad a total rebuild would be quicker for this map.

In this case you should save and rename the map. Then systematically go to each displacement, destroy it and look at the base geometry that displacement was made from.

I think in this case the map was de-complied with who knows what compiler and that is why there are errors.

Your map may only have a couple of places to repair, in this case there were too many errors to save the map.

This issue can also be...

1. Displacements that are too big, destroy them and make smaller sections, sew them together.
2. Skybox displacements when resized are now too small, again when making the skybox be aware of that and don't make really small/thin sections when making a skybox before scaling it down. Again...destroy them and rework them.

This error is very hard to resolve, finding these bad displacements is hard.

A combination of using the cordon tool as in the above section and also as a last resort making a new VMF and systematically destroying displacements, then compile and count the errors.

In some cases the compile log may not give a error, then the error appears in game.

One thing is for sure, it comes from bad displacements.

So in the stage when making displacements... use the Run Map and compile as you do displacements... especially after scaling the skybox. If the errors appear, its likely the last item you edited.

 

 

 

Day Of Defeat:Source Ladders

Recently after making waypoints for RCBot2 (nearly) every bloody ladder was a problem for the bots. They would bounce off them, stick to the bottom or not exit them correctly.

Think of the bots as a human who is just learning the game, limited capacity in the mouse to movement keys coordination.

Yes... humans have issues too if a ladders isn't made correctly. I'm looking at you...fuckin Orange map makers.

Rather than repeating the entire saga here, go off and read that section to see what makes a good or bad ladder.

There are some rules when making ladders, after you observe them you will find using them a lot better.