distorted lines

[gilowoskian]

Using keyshot with Rhino.

I cant figure out where these lines are coming from. I dont know if it is keyshot putting them in or if its from the model. Kinda looks like it has ribs and a bad fairing job. The surface was a 2 rail sweep so i know its smooth its not like i lofted sections together. Also could it be the mesh setting in rhino that i need to change? If so what should i set it too.

any help on this topic would be greatly appreciated.

thanks,
jake

[Speedster]

Very interesting.  I got the same kind of streaks on a recent render, cropped detail attached.  On mine it looks like mold or something, under the soffit and under the cabinet doors.  I've seen similiar on other renders, but never bothered to ask why- I just Photoshopped them out.  But on your beautiful model they are very distracting and odd.  My model is in SolidWorks.

Hopefully someone has a clue or clues. 

Bill G

[Speedster]

Oops!  Forgot to attach the image.
BG

[gilowoskian]

yea idk where they are comeing from. I mean im no expert in either program but im pretty sure its not the model. Ill try to render in flamingo tomorrow and see if they show up.

ps. thanks for the complement

jake

[KeyShot]

The lines on the boat are caused by the tessellation being too low. Try increasing the accuracy of the tessellation inside Rhino.

[PhilippeV8]

I get those too sometimes ...

I always import my scenes with chordal error 0.02mm into 3D Via and from there I save as an OBJ file which I open in KS.

Strange though that we get these weird shadows on strait line parts as well ... ?

[trice1]

Nice yacht even with the strange lines.

[gilowoskian]

k ill try that. Is there any preferred settings in rhino i should use when considering to render, or do you know where i can find this out. Im pretty much self taught so i dont know all the advanced features.

Thanks everyone for the complements.

thanks
jake

[Speedster]

Not sure if it's tessellation.  There are no curves or radii on my kitchen cabinets, for example.  The "mold" does not appear on other materials like metals, plastics, etc.  Only on "painted" surfaces.  The choice of HDR makes no difference.
Bill G

[gilowoskian]

I can test your theory really quick by appling a meteral other then paint to my hull. Ill let yall know what happens

[Robb63]

I get this occasionally too. Almost always with a lighter color painted material. It may happen to me with light plastics too.

My mesh settings in Rhino are always the same, and I get amazing results on most of my models in Rhino so I don't know that it's the tessellation?

[KeyShot]

Bill,

For the kitchen you will need a higher value for global illumination accuracy. It is a different issue than tessellation.

-- Henrik

[Arnaud]

Some informations about Rhino' mesh

1 - Keyshot doesn't read the geometry and doesn't make any tesselation on Rhino's objects. It only read the existing render mesh created by Rhino. (if you use Save Small option, KS is unable to read anything into the .3DM file)

2 - Inside Rhino, it's possible to change the render mesh options : goto Options > Document Properties > Mesh
Default option is Jagged & Faster. That means a "coarse" render mesh , but faster view manipulation (rotate, zoom, ..)
if your graphic card is fast enough change to Smooth & slower , but also all modelization process will slow down , because operation like Join / Explode / Trim / Boolean need to re-compute the render mesh.

3 - You can also switch to "Custom" options. In this case there are many parameters described in Rhino's help . Generally I play with "Maximum angle" (angle between triangle normals, or between surface normal and triangle normal). Lower values increase the number of polygons. No effect on planar surfaces because all the triangles have the same normal, but usefull on shaped surfaces.
"Maximum aspect ratio" could be also useful. A value in a range of 1 to 5 forces Rhino to compute regular quads, avoiding highly distroded polygons.
Also Minimum initial Grid Quad is efficient to change the mesh density. In this case, set all other parameters to 0 and increase the value to get more polygons.

Below is an example of 3 different parameters on a simple shaped surface.
- at the base : Nurbs object with default "jagged & faster" option
- middle : mesh created (Mesh > From Nurbs Object) with fewer polygons
- at the top : mesh created with "Maximum angle = 5" and "Aspect ratio = 2"

I made quickly 2 rendering, with a white paint. the effect of tesselation is visible on the border of the surface but also in the concave face of the surface.

[gilowoskian]

Arnaud

thanks for breaking it down, though some of it kinda goes over my head. Im not very knowledable on this topic. I was never taught this, people who i know who use custum all tell me there settings but have know idea why they use it, other people told them thats what to use. But im assuming i should be able to get by with smoother and slower for now. They were all set to jagged  

Which Brings me to my next question.  

Can you update the model from keyshot after applying these settings in rhino?

It would be a real pain to have to reapply all the materials and settings to such a big file.

I tried to open a new file cause i think thats only way i know to do it and it just errors reading all my rhino files. I used block links to keep the file size down in rhino. Any ideas why?

other files i never used open fine.

[gilowoskian]

Yes now i have a different issue i cant import these models without using, advance, old importer. and they dont always appear in keyshot. and i never had a problem with keyshot reading rhino files lik z bieng up and now its bringing them in on the y axis being up. I dont know what old importer even means did keyshot update to a different importer.

Im just getting frustrated now lol.