Hi everybody!
I thought I'll post my latest tests in a new thread, to start of fresh. Yet pickin' up our discussion here:
https://forum.corona-renderer.com/index.php/topic,7538.0.html
Over the last two month I have been dealing a lot with new CAD data provided by the client, i struggled day and night and tried a bunch of the major CAD translation packages out there (well, DeltaGen is yet to be tested ;).
To be more specific:
- Maya
- 3dsMax directConnect
- 3dsMax nPower Translators
- VRED Pro
- Showcase
- SAP Visual Author
- Transmagic (to check for any CAD file problems)
The original data was provided through SiemensNX. I yet have to ask for any kind of polygonal data format (like JT) to be provided directly. This way I will be able to test wether tesselating the modell natively without STEP conversion yields any better results...
I can confirm what Ondrej said before: the tiny triangles are the issue. After importing STEP as a rough mesh some of the areas cleaned up. Yet this is not an option for hiRes obviously.
Besides of that I tried using 3DCoat and Mudbox to retopologize the data into quads without luck. There is a new paper for a nurbsToQuad workflow, but it has to be implemented by someone:
http://www.sciencedirect.com/science/article/pii/S0167839614000624In the screenshots I have collected some results of my testing. You can clearly see that Maya produced clean "unbroken" mesh in places, where there was a solid Nurbs > Quad Mesh conversion. To clean up all the surfaces Maya produces would still somehow defeat the purpose - i do require a simple translator solution for everyday work.
The errors are highly resolution dependent - you might not see the black lines appear on low res, but since most of us are doing high res in production...
I merely wanted to point out the problems I've been having with CAD data for the last two month, I understand that Ondrej is working hard on many different things.
Nevertheless to my mind CAD data conversion / translation / teselation (call it whatever you want ;) ) shouldn't be last priority. I believe there are a lot of people out there like me willing to use Corona for any type of industrial viz.
As for me, unfortunately up till now I had to stop using Corona for CAD - every model turns out to be a pig in a bag. The only option left is to do clay rendering turntables over night (or days!) just to see if any broken normals appear.