City sample in houdini can't process and export

Development World Creation
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46

for me, houdni 18 python 2 version and UE 5.03 works on freeway

47

Are your buildings fine too? Have roofs etc?
Can anyone be so kind and share fixed houdini files? I try to apply fixes in this post, but even with that I still can’t even get till export.

48

If you are using py2 version of Houdini you should not be needing any fixes. Roofs and freeway exists are still not working for me.

49

Well it yells about parentheses, and when I try to fix it, new window appears with bunch of errors

50

Parentheses error should only be happening when using Houdini with py3. Are you sure you are using ‘default’ version and not py3 version of Houdini?

51

You are right, for some reason I had py3, so I manage to export, but have issue with roofs.

52

it seems roof data is not exported correctly, neither py2 nor py3.

53

I have issue also with ground, in some parts there is gap between ground and the building.

54

Getting same issue when importing geometries, can you describe your solution please ?

55

I do not have solution for this.

I can export PBCs and Geometries from Houdini (without using PDG, since when using PDG getting an error about missing Building_Generator_PDGed.bgeo.sc file).

It looks like that when executing RuleProcessor_City rules in UE5, Small_City_Full_buildings_Roof_Geo rule, which seems to be responsible for generating roofs of complex non-rectangular shapes, does not do what it is supposed to do.

I can see meshes corresponding to roofs and floors in Geometry folder SM_arbitrary_roof_N and I am pretty sure that these are the missing roofs that had to placed by Small_City_Full_buildings_Roof_Geo rule in appropriate locations.

I am not a Hoidini expert, so so far I haven’t been able to move past it :frowning_face:

56

Small_City_Full_buildings_Roof_Geo don’t do anything becouse CITY_buildings PBC don’t have roof data for some reason when exported from Houdini (so something is broken in Houdini).
I reexported untouched Small_City.hip, resoults are simple:

  1. If you use exported CITY_buildings for Small_City_Full_buildings_Roof_Geo, no roofs
  2. If you use CITY_buildings from City Sample/City/Small_City/PBC and use it for Small_City_Full_buildings_Roof_Geo, you have roofs
  3. If you use CITY_buildings that was exported already in a CitySample_HoudiniFiles.zip, you will have roofs
    From all this I can tell Houdini don’t save roof data in CITY_buildings PBC for some reason.
57

The meshes for the missing roofs are generated and can be found in Geometry folder named as SM_arbitrary_roof_N, but they are not being placed to the appropriate locations of the map. I would assume that this is what should be done by Small_City_Full_buildings_Roof_Geo rule.

58

Yeah I was referring to crash issues when importing geometries (bgeo), I understad that you used source build of the engine and added a null pointer check somewhere to avoid getting crashes upon import. Can you tell more about how you managed to actually get these bgeos imported.

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60

I’m using 5.1 but did try with 5.0.3 and it crashes as well. Worth mentioning is I did the import with 5.1.1 which shouldn’t but could (?) make the difference. I’ll report back whether the rules import does anything at all.

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61

Now additionally it is worth mentioning that the rules import did work for me when I was importing just the traffic data off of small city PCB (5.1), so something breaks when exporting the PCBs out of Houdini. I need to check whether small city geometries do crash the engine, otherwise it’s on the houdini export fault.

62

I recall I had some crashes with 5.0.3 as well, but then they disappeared. Any chance you still have stacktrace from the crash?

63

I can get you one for 5.1 if you want to have a look at it.

64

Thanks, no need, I remember that for 5.1 it was some null pointer exception and it really looked like it was caused by a bug in UE code - an incorrect check for null pointer in for loop.

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65

After some emotional break downs, I can confirm I found a solution for crashes when importing PCB or bgeo data. I used a 5.0 plugin that came with 19.5.368 Py.3.7 install of Houdini.

First you have to recompile the plugin if targeting 5.1, secondly you won’t be able to create houdini session from the get go. In order to setup a valid session you’d have to put in your houdini installation bin folder path inside plugins settings in UE (need restart after that), secondly you’d need to go to houdini Windows->Houdini Export Session Sync and set it to named socket, leave the rest default. Back to UE Houdini Plugins settings and set a named socket there as well.

You should be able to create a session now, I was able to import all required data that’s been generated with houdini as well as run rule processor with these.

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66

Now tell me that you managed to get the roofs? :slight_smile: