How to aviod floating point artifacts when snaping meshes

Hello Community.

This topic has been discused some times, but somehow i can't find real working solutions.
I'm trying to create some modular gameassets, but i cannot get them aligned perfectly.
There is always some artifacts between them, wich only occur at certain camera angles.



As far as i know this is a floating point precission problem with the verts sharing the same position.
What i dont understand is, that unitys standart assets like cubes and planes dont suffer from this problem.
(at least i was not able to create this artifacts with them)

My assets only align if i completly add no rotation and put them on full value positions.
Even 90° rotatations cause artifacts to appear.

I tryed changing import settings, scaling them from 1.1 to 1.0000001 , overlapping the meshes a bit, with and without the outer hidden faces...
nothing helped.

Some say its because these meshes are not merged, but that would be the same for 2 unity standart cubes / planes right?

But there are people having modular assetpacks in the asset store and people giving them good reviewes.
So i asume there is a solution to this problem?

- I know i could hide the seams with other objects, but that isn't an option in all cases
- I know i could merge everything in my 3D software, but thats not an option for assetpacks.
- I would like to avoid having a script that merges everything together

Does someone have any informations or solutions for this issue, that i havn't found so far?

 

I would point out that same "seam" is showing up on the edges of the arches regardless of if they're next to eachother or not. That makes me think it's a texturing problem of some kind, or you're rounding the mesh corners.

 

the artifacts also appear without any textures and flat shading

 

Then are the mesh edges beveled?

 

There is a possibility also that your FBX (or other exported mesh) is at some sort of float-precision-breaking scale.

The model itself could also be at fault, it's more likely that you've given the edge verts some ridiculous value for their positions. (i.e. something like 1.9999999 instead of 2) so check that in Blender also. (I say that because I can see you used blender to make them. )

Also, try beveling as bgolus said, that can help hide errors like this. (Even a small amount of bevel can add a seemingly intentional creased edge at the seam)

EDIT: One more thing; how big's your draw distance? A huge far clip plane WILL cause issues with camera movement bugging everything out.

 

Turns out you Guys where absolutly right about the bevel/rounded corners.
I now tripple checked everything to be flat shaded besides the inner arch and it seems to work



Now it starts looking like something to work with

Thanks to both of you for the quick help and feedback

 

Heh... being that it fixed I for you, I should probably follow my own advice and fix up a couple of bugs in my own project... (My dynamic track generator sometimes slightly displaces pieces, making edges at seams visible)

 

Hi I am having a similar issue but it only seems (no pun intened ) apparent with Unity 5.x and not older versions. Also these seams, seem to affect physics as well as I have modular golf course pieces and the ball rolled perfectly flat before over the seams and now it trips over these seams.

 

Well in my case it was a texturing problem.
If it affects actual physics as you say, then its seems to be an issue with the meshes not fitting perfectly.
Try placing meshes and the connection verts only on full number coords not something like 1.000003.
Try using 90° steps of rotations.
Try to resnap them.

 

Hey b4nj0 I believe I tried all those things to no avail.

Edit: I noticed on one of the parts that has an issue. It somehow ended up with a rotation of -89.98019. So I have it rotated back to -90 and saved it. When I reload the level, the part is returned back to a rotation of -89.98019

WTF

Edit2: Damn I thought the bug i reported re:rotations (759115) was fixed but it's not yet.

Edit3: Please vote for https://issuetracker.unity3d.com/issues/transform-rotation-value-changes-on-play-mode-a-little-bit