Author Topic: Obj issues  (Read 617 times)

Offline midnight.mangler

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Obj issues
« on: March 19, 2019, 07:21:11 PM »
Hello All

After having a Terragen license for many years and not diving in, I brought my maintenance current and have been tinkering. So far, really loving the realism and ďthe lookĒ possible in Terragen with my limited skills and excited at the possibilities :)

I am having a bit of trouble importing an obj. Itís a mesh I built (not the greatest I admit). It displays perfectly in Modo (which I use as my exporter) and imports perfectly into blender.

In Terragen though at boundaries of the mesh it shows some polys as either missing or transparent. Any tips on why this could be happening? I see some suggest poseray as an option to export objís that Terragen likes - I have not been able to test that yet but wanted to see if there is anything else I should be aware of. Thanks for any tips.

Offline archonforest

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Re: Obj issues
« Reply #1 on: March 19, 2019, 07:35:55 PM »
Perhaps u can upload the obj file so it can be tested.
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Offline digitalguru

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Re: Obj issues
« Reply #2 on: March 20, 2019, 12:42:31 AM »
it sounds like some of your faces have flipped normals, I don't use Blender but it might display the faces correctly regardless if the faces are flipped or not.

Maya has a command called "conform" where the flipped normals are reversed to the same direction as the majority of faces so they all point the right way.

Actually just looked it up and Blender has a function called Recalculate - https://blender.stackexchange.com/questions/12165/how-to-make-all-faces-flip-to-the-right-consistent-direction

Run that and re-export to Terragen.

Offline midnight.mangler

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Re: Obj issues
« Reply #3 on: March 20, 2019, 08:16:28 PM »
Thanks - I think the flipped normals is the problem. When I use the analogue of modo's "conform" command the mesh then shows the characteristic holes of flipped polys - which is strange.

So something is screwy with the mesh. I'll keep tinkering.

Offline Oshyan

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Re: Obj issues
« Reply #4 on: March 25, 2019, 07:23:09 PM »
Also avoid use of Quads.

Edit: nevermind, I was incorrect.

- Oshyan
« Last Edit: March 26, 2019, 06:08:58 PM by Oshyan »

Offline midnight.mangler

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Re: Obj issues
« Reply #5 on: March 26, 2019, 12:09:34 PM »
Thank you Oshyan! You rock! That fixed the issue immediately.

Soooo happy!!

Offline digitalguru

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Re: Obj issues
« Reply #6 on: March 26, 2019, 12:51:20 PM »
Quote
Also avoid use of Quads.

Really? Why is that?

Offline masonspappy

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Re: Obj issues
« Reply #7 on: March 26, 2019, 05:23:42 PM »
Quote
Also avoid use of Quads.

Really? Why is that?

Wondering the same thing.

Offline Oshyan

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Re: Obj issues
« Reply #8 on: March 26, 2019, 05:50:50 PM »
Sorry, I was mistaken, quads shouldn't be an issue. But apparently it fixed things anyway? :D

- Oshyan

Offline digitalguru

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Re: Obj issues
« Reply #9 on: March 26, 2019, 06:01:40 PM »
Never had a problem with quads in any of my imported objs - though I always check for face conformity etc before I export them

Just seen your post Oshyan - maybe the triangulation command re-oriented the normals automatically
« Last Edit: March 26, 2019, 06:03:11 PM by digitalguru »

Offline Asterlil

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Re: Obj issues
« Reply #10 on: March 26, 2019, 10:39:00 PM »
By coincidence, I have just tried to import an obj file from Blender to Terragen, and have run into this same problem.

Two attachments: first the Blender file, a screen grab that shows that all the normals are as they should be. There are no texture images and the model is consolidated into a single mesh. Second is what it looks like after being dropped onto the terrain (the purple thing is my marker object cube).

Eh. The first attachment didn't stick. I'll post a second reply.






Offline Asterlil

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Re: Obj issues
« Reply #11 on: March 26, 2019, 10:40:46 PM »
The original Blend file.

Online bobbystahr

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Re: Obj issues
« Reply #12 on: March 26, 2019, 10:52:56 PM »
Have you tried running it(th .obj file) through PoseRay to correct the parts shaders configuration?
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Offline midnight.mangler

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Re: Obj issues
« Reply #13 on: March 27, 2019, 09:54:12 AM »
Sorry, I was mistaken, quads shouldn't be an issue. But apparently it fixed things anyway? :D

- Oshyan

Yes it did. Itís a complex mesh. On Modo it was displaying fine - until I used the modo command to align all the normals. Then I started to see holes ;-) which is curious. It could be as somebody speculated that triangulating it somehow introduced a consistency check that aligned the normals correctly. I am not sure other than - it worked ;-) I was completely stumped as to how to fix it.

Offline Hannes

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Re: Obj issues
« Reply #14 on: March 27, 2019, 01:46:28 PM »
Asterlil, what Bobby said. I run almost each and every object, I want to use in TG, through Poseray, go to "Groups" and recalculate normals. Most of the time this fixes such normals problems.