Terragen3 (v3.4 build 3.4.00.0) Renders Fail After Importing .obj

[MinusD]

I've been using my licensed copy of Terragen3 for a while now, successfully rendering landscapes with imported .obj files.  However I have started to experience failures in which the render pane fills with blue and white squares, before eventually the render ends up a solid black.

I use the free version of Sketchup 2016 to generate a .dae file, and I use Blender v2.76 to convert to an .obj file.  I have uninstalled and reinstalled both Sketchup and Blender, without effect.  I have also done a REPAIR on my Terragen, though not a reinstall, without effect.   

I need advice on how to track down the discrepancy.  Help!  Thanks.

[bobbystahr]

I'm running 3.4 as well and haven't experienced that. If you're not on a mac try running the object through the free PoseRay:
https://sites.google.com/site/poseray/
and there also seems to be, according to Mr Google a mac version though I know of no one who's tried it:
http://users.skynet.be/smellenbergh/poseray.htm

[bobbystahr]

And if that gives no release try uploading the object and .tgd and I/we'll take a run at it here.

[Kadri]

Just a guess but have you tried to use just basic textures-shaders-colours ?
I had sometimes problems with transparency, reflection, luminosity(not sure about this one); especially with high values.

[MinusD]

Thanks, Kadri.  Yes, I've tried very simple models in SketchUp, with no colors or textures;  but anything I model as .dae, convert to .obj using Blender, and import into T3 since the event causes Terragen crash.

The Event was my Windows7 OS being upgraded (without my knowledge, during an overnight render) to Win10, and then being backed out and restored to Win7 by me.  There may be no causal chain but the timing seems suspicious.

I have since performed the upgrade to Win10 again, and gone through some registry repairs with AVG, etc, to no avail.

[MinusD]

bobbystahr - thank-you for your offer to try to troubleshoot the issue!
The attached .zip contains (I think) all the pieces of my broken toy.  If the zipped format is problematic let me know.  -Dave

[MinusD]

P.S. I am working on the Poseray recommendation now....

[bobbystahr]

I voluntarily upgraded to 10 a week or so ago and have no real problems except my slow older dual core dell, not really up to TG

[MinusD]

SUCCESS.

PoseRay exported an OBJ file that I could render successfully in my T3.  Bonus: I cannot be certain from the low-res rendering but it looks like arcs in PoseRay.obj files may be higher precision than in my Sketchup.dae/Blender.obj models.  If true this will be a welcome turn of events.

In any event, although I am still troubled by the change in my system that I don't understand, I am very grateful for your help in arriving at a workaround!  And, I think PoseRay is going to be very helpful beyond converting .dae to .obj format.

Thank-you for you quick responses, bobbystahr and Kadri.

Best regards,
dave

[Kadri]

The problem is the "-1" value of "Index of refraction" in the material shader of the object.
When you change it to something like "1" it renders without a problem.

[Kadri]

Looks like any negative value is problematic for index of refraction.

[bobbystahr]

The problem is the "-1" value of "Index of refraction" in the material shader of the object.
When you change it to something like "1" it renders without a problem.

good catch, never noticed that, just took it straight into PoseRay and U/V mapped it and it works fine as well...the mapping must have fixed that.

[Kadri]

Yes probably. Poseray is like a multipurpose fixer for Terragen OBJ imports

[MinusD]

I don't know where or why I would have set I of R to a negative value, though I have done so in Terragen with displacement...  But I'm off to explore this situation now. I love a mystery! 

Thanks to you both, once again.  I was about to become distraught, before I got properly connected to the PlanetSide Brain Trust.
[attach=1]

[MinusD]

Kadri - I located the offending negative Index of Refraction value, down in the network node.  Strange, because I  have not yet tinkered with network nodes.  Correcting the bad value fixed the render problem.  I wonder how I managed to get it set to [-1] in the first place, but I can move forward and will keep this new knowledge in mind.  Thanks.