Gaps between surfaces! URGENT HELP!!

[radicalgel]

Hey Guys,

I was following the vacuum cleaner tutorial that comes along with Alias documentation. After completing most of the tutorial I realized that there was these gaps between the surfaces where a filleted surface had been created. These are visible in the viewport and look worse in renders. Is this normal and is there a way to solve this issue. I badly need to model something for a project and I cant show a render with these flaws so I would be really grateful if someone could pls help me.

PS: I have linked screenshots to give a better idea of the problem I am facing.

http://img518.imageshack.us/my.php?image=gapsxi8.jpg Edited by: radicalgel on Nov 7, 2008 7:54 AM

[dfleury]

These are typically not gaps between surfaces but tessellation artifacts. Refining tessellation parameters should do.

[radicalgel]

Hey thanks so much for the quick reply. I just changed the tessellator from Fast to Accurate but I still had to pull the Tolerance slider all the way to minimum (0.00100) in order to get rid of "most of" the artifacts. Is this normal? Even if I go down to 0.0001 i can still see a few artifacts. I also had to do the same in the render settings to clear most of the artifacts from rendered images. I was just wondering if I'm going about this the right way or am I missing something? Why am I, in spite of taking the tolerance so low, still ending up with one or two artifacts?

[manish09]

Hi mate, when doing test/final renders, go into Render>Globals> and set Global Quality Parameter to high and check that the Tessellator underneath it is set to Accurate not V9 also check your Mesh Tollerance is atleast 0.00500....check attached file....Hope this helps...
Manish

[radicalgel]

Thanks Manish!

Actually I have set the globals to High Quality and Tessellator underneath it is set to Accurate (Tolerance = 0.00100) and am still getting one or two artifacts. 😞 Dunno y! Also I am unable to access your attachment, I'm getting some error so could you please upload the screenshot on imageshack or somewhere and link me to it.

Heres a link to the render with the following settings: -
Quality = High
Tessellator = Accurate
Tolerance = 0.00100

http://img152.imageshack.us/my.php?image=artifactnw1 .jpg

[tekbot]

hate when that happens. what version are you using?

try this.
1.
-hardware shade settings > quality > user define > ...
-turn on "show triangles"

this should show you if it is just a bizarre placement of the triangles or if it really is a issue.

if its jacked up placement, then the you can use the "edge length" settings to control this. careful the poly count could get out of hand.

2.
anti-aliasing usually helps.
i like the smooth and the hardware shade antialiasing. for smooth to work you have to turn it on in the general prefs. 2009 now has the antialiasing in the WindowDisplay toggles.

3.
stitching it will fix these areas for Viz but i would not recommend using this version to continue working. the tessellator will look at the edges as if they are joined and match the poly edges. "crackless tessellation"


4.
if these options dont work... maybe your surfaces do need a message. : )

[radicalgel]

Hey thanks!

I tried all the stuff you mentioned but still no real luck. 😞 I use alias 2009! I still cant get rid of one artifact no matter what I do.

[dfleury]

Sometimes you see the artifacts in real close up but when looking at the object as a whole you won't.

Try posting the Wire file you are having a problem with so others can take a look. For helping fining the spot with artifacts you could create a bookmark or with an annotation. Edited by: Damien Fleury on Nov 8, 2008 10:59 AM

[radicalgel]

Hey sorry for the late reply. I have uploaded the wire file and provided the link below. The artifact which persists is located in the top right portion of the handle fillet. If you zoom in there and render you will be able to see it.

Link to WIRE File: http://www.sendspace.com/file/jr0zlt

[dfleury]

The quality of your SurfaceFillet is no good. It has some twist and gap if you look at it closely.



It looks like your SurfaceFillet was created with version 2009. I simply rebuild it in 2009 SP1 and it is much better.



You can compre the results with the attached Wire file. Open the file, look at the "magnified persp window" and switch between N2009 and N2009_SP1 layers. You will immediately see the difference. I killed the history of the data on the two layers to make sure it doesn't get rebuild and messes up the comparison.



With the new data there is still a small artifact in the Diagnostic Shade close-up but nothing really visible in the regular Pers window nor in Direct Render with Global Quaqlity Level set to High.



--



On thing to be aware when modeling in Alias are Construction Option settings. The gaps seen in your original file are ok based on the tolerances given to Alias for building geometry. To get tighter models you'll have to tighten your settings - at the detriment of slightly longer computation time and heavier surfaces. There should be expalnation about this in the LearningAlias book.

[radicalgel]

Thanks so much Damien for all the help. Guess I gotta be more careful to make my model tighter while surfacing them. Will try and redo this tutorial with my own settings and see how things go. I just got SP1 so i guess that should help too.

[jankiz]

Thanks so much ! Under user defined adjusted the tolerance to 0.01 and Woila  !