Question and Observation about Terrain.dll crashes

[Afterburner 374]

Hello,

I have a question about the terrain.dll crash. In the AVSIM CTD guide, it is mentioned that this error "Usually indicates high scenery/terrain settings, especially Autogen. Rebuild FSX or P3D.cfg. Restart sim to see if the error reoccurs. Most of the time, the error occurs on a whim."

However, I think that there is more to it than mentioned. A while ago, I encountered this crash during a flight. After taking a look at the scenery library, I found out that the positioning of some add-ons was messed up. For example, due to circumstances that I have already resolved, FTX Central placed ORBX Vector at the very top of the scenery library and left out the airport elevation corrections. Later, after resolving the issue and letting FTXC put the entries in the proper order, I performed the same flight with the same variables and settings, and this time no crash. I remember having rare terrain.dll crashes in the past, and it turned out that some scenery add-ons contained possible incompatible elements (e.g. FSX add-ons that were used in P3D), or the scenery library order was not appropriate. In my example, having ORBX Vector atop an ORBX region could have created all sorts of conflicts that culminated in a terrain.dll-error. After all, the name of the error indicates that there is something wrong with the terrain, which is likely to be caused by a conflict of add-ons.

In this regard, if there are no such conflicts, why would high scenery/terrain settings cause this error?  I understand that higher settings put more load on the PC, but the computer also responds with a slower frame rate. Yes, increasing autogen settings requires the CPU/GPU to work harder, but on the other hand, they have more time to render autogen objects as a result of decreased FPS. If higher scenery settings per se caused the crash, wouldn't it make the program itself faulty (assuming that the hardware has no faults, e.g. due to a bad OC)?  Am I missing something? Isn't the root cause more likely a scenery conflict, as described above?  If you push the scenery settings higher, it actually makes it more likely to display objects that trigger the conflict, resulting in a terrain.dll error.

I thought that this information would be valuable for the CTD guide. Also, please explain the rationale behind high scenery settings potentially causing a terrain.dll crash if there are no add-on conflicts (or if you use vanilla P3D).

[Jim Young 2,356]

Thanks for the information.  I was told by developer's in the know about developing scenery that the terrain.dll does not care where scenery is located in the scenery.cfg.  It does not even monitor that at all.  I had the same thoughts in FSX but was not so nicely told I was wrong.  I could understand the terrain.cfg in the scenery.cfg folder getting corrupted (but not by scenery layers) but not the terrain.dll.  All configs are subjected to corruption at some time depending on whether or not there was a lot of changes made to it over the years.

I don't know much about Orbx Vector scenery but my understanding is it replaces the default scenery.  I don't have any Orbx scenery installed anymore but a crash can be caused by that scenery.  For instance, if it is calling for an object or texture to render and cannot find it in nano-seconds, it might trigger a crash.  Again, high settings might enhance the possibilities of this happening.  I don't know whether it would be the terrain.dll shown as the error though.  It could be a StackHash or ntdll.dll error too.

The AVSIM CTD Guide provides suggestions for fixing an issue based solely on Internet searches (we do the searching for you).  These are suggestions that fixed the problem for others.  Now, high settings may not always be the cause as the terrain.dll error periodically shows up and future sessions no one sees the crash again.  It could have been scenery indexing gone wrong (from high settings) or something like that.  I personally have my settings set to the max in most areas and have yet to see the terrain.dll error.  Saw it a lot in FSX though. 

The AVSIM CTD Guide is mostly an investigative tool.  It has several suggestions for investigating the scene of the crime (or your CTD).

I wish the AVSIM guide could provide a solid solution to each crash but, if everyone was getting a crash in the same scenario, then I would suspect the developer of the add-on scenery, aircraft, utility would fix it.  It is add-ons that create the most problems for simmers.  I would be shocked if anyone got a terrain.dll error or any other error using P3DV4 only and in default mode.

Best regards,

Jim

 

[Afterburner 374]

OK, thank you for your explanation. The terrain.dll may not care where the scenery is located in the library, but I think it does care whether there are any conflicts or not with another scenery. For example, ORBX Vector has correct roads, bridges, rivers, etc, and this add-on normally belongs in the library below city- and airport add-ons that bring their own data for cities and roads. If you placed ORBX Vector above the latter, there may be some conflicts between the two. What is written in the guide sounds like high settings are per se to blame for terrain.dll, which - as you have written - is very unlikely to occur if you run vanilla P3D.

[Jim Young 2,356]

38 minutes ago, Afterburner said:

The terrain.dll may not care where the scenery is located in the library, but I think it does care whether there are any conflicts or not with another scenery.

That I can agree with and maybe that should be included as a suggestion in the CTD guide.  If incompatible, it throws the terrain.dll.  I cannot go along with Orbx Vector as the issue or else everyone who owns Orbx Vector would be seeing the same problem.  An incompatibility with a scenery not specifically developed for 64 bit applications is the most likely cause.

[Lobos 0]

Hi, I was having the same error terrain.dll, I uninstalled all of my Orbx global, vector, all land classes, regions, airports everything Orbx and haven't had a problem since. I spent a lot of money on Orbx and had nothing but problems with their products and Prepar3d any version. Now I just fly Prepar3d v4.4 and VRS Superbug and enjoy the sim with no problems and the scenery is not as good as Orbx but I just got tired of always chasing the sim to make it work properly with Orbx products. I agree with Jim about the incompatibility issue and if you look on the Orbx forums there is a lot of unanswered problems there. I have GEX and UTX and tried them with the same result, I even tried Orbx and UTX together nothing but problems. With 3rd party developers that replace the games textures your going to run into that error sooner or later.

[Alaaar 34]

Hello all, I just had the terrain.dll crash last night, right at the middle of the Atlantic ocean  800nm before arrival to CYYT, I did the flight again without changing a variable or editing or modifying anything (except for the number of passengers and baggage)...It went alright,

What I think is, some errors are identifiable and easy to know the cause and some don't, probably because of the poor coding of the original FSX now developed to P3D...... 

I think P3D is a much more stable platform but it's still screaming I am FSX in disguise in some sort  

[pgde 571]

I think 4.5 was supposed to fix the CTD over the Atlantic.