Mesh won't render correctly

When adding edge split modifier the mesh won’t render correctly. Here is the filesflowchart Animation test.blend (922 KB)

Could you be a little bit more specific? What exactly does not “render correctly”?
To me the mesh looks right with the Edge Split modifier, but wrong without (because you have smooth shading on a flat surface).

The green arrow render with artifact. There is already a solidify modify. Shouldn’t the solidify considered the mesh as solid instead of flat? As I put the edge split below it.

Even if I applied the solidify modifier, the error still remain.

I meant “flat” in a surface shading context, not a geometry thickness context… The top of your arrow is supposed to be “flat” (= not curved). Yet you applied smooth shading all across that mesh, which will give weird results. The Edge Split modifier takes care of that, as it evaluates all surfaces of that mesh and decides whether to shade them flatly or smoothly.

Could you post a screenshot of that artifact? Somehow I fail to see that here:

This one I post is flat but there also curved path which I have to put smooth shading instead of flat. And the artifact remain

flowchart Animation test2.blend (710 KB)

Are you using 2.71 on Windows?
I suspect the issue is not the Edge Split modifier, but the Motion Blur, which is buggy as hell on Win 2.71:

I’am using build 2.71 11332 x64
Even the silo was black on blender 2.7

Thanks. Motion blur off help.Here is the screenshot about the silo problem. Motion blur off.

Hmm. I don’t see that here - neither in 2.71 nor 2.70a x64…?

You have something bad on that tank geometry. I’d say get new one ;).
Yes, on a preview it’s fine yet black on render. I deleted most of it, recalc normals and it got normal. Check base cylinder too.

Edit: Motion blur does the same on Linux too btw.

Hi. Yes on blender 2.70x64 its render fine. I haven’t try on 2.71 official build but 2.71 on graphicall. And I get this black render on almost all 2.71xxx build which appear only while render, not on the cycles preview viewport.