Flipped Faces
mirjagirl
Posts: 85
Is there any way to solve the flipped faces when importing an OBJ from Blender to Daz?
The higher the poly count, the more flipped faces.
Individually, the faces flipped are zero.
Once joined and 22k, anywhere between 3 and 5 flipped faces, consistently.
Is there any fix for this?
Post edited by mirjagirl on
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Are you sure the faces aren't flipped in Blender? (I haven't had this bug and I import from Blender all the time - when I've got flipped faces it's because they were flipped in Blender during modelling). Use the overlay that paints faces blue or red depending on normals.
Failing that - there's the geometry editor to select and flip the offending faces.
No flipped faces in Blender.
I've recalculated normals
No loose geo
I've redrawn the offending faces.
Nothing is 'wrong' in Blender; all good.....until you import the obj into Daz. Flipped faces.
So, I clean the 'flipped faces' in blender, one by one.
Double check everything is clean.
Once I Join, re-export and import into Daz.....flipped faces.
I'm bald.
As I understand it, the geometry editor (Daz) will flip all faces and can't be used to select individual faces. Is that correct or do I have it wrong?
These are simple Mesh Planes. The reason they're Mesh Planes is because
Mesh Cubes created the same issue
Solidify Faces via the FACE dropdown created the same issue
Solidify Faces via the Modifier created the same issue
Extracting faces from the Mesh Plane (without any shaping or modification at all) created the same issue.
This is my "I got nothing else to try" attempt and I'm having the same issue.
The Front and Back sit atop each other with .04 space between them on the Z.
If this were just happening on MY handiwork, that would be one thing.
But I can create a NEW Mesh Plane, in a new file,
subdivide the face 1000 times for a sim
Export to OBJ, Import to DAZ: CLEAN.
Go Back to Blender, Solidify (any way) or extract the faces,
Export to OBJ, Import to DAZ: Front clean, Back DIRTY.
These are two flat planes, .04 diff on the Z, Joined UV.
That's it.
I'm Bald.
I'm Bald.
I'm Bald.
when blender is stupid about the normal direction (flipped faces) I run it through uvmapper pro or uvlayout to get things all pointed the same way
oh wait this is two layers of mesh? first off .. why? also give it a mocrobevel on that edge, just a tiny flat edge at 90 degrees I bet DS is getting confused
LM
I will try the microbevel. Hopefully that will solve the repeat issue.
2 layers, see 'last ditch effort and hair pulling' above.
As far as the two programs go, I don't see spending an extra couple of hundred $$ on this 'hobby'. Maybe if I come up with another 'brilliant' idea (or get through this one), but not at my interest level.
Again, I'll try to bevel and see if that solves the issue, but that does not explain why it also appears with Solidify or Extract Faces. All of which I have already tried.
I'll try the bevel and let you know.
The bevel is a great idea, but will not work in my case.
Because everything else has failed, what I have now is 80 individual sections. The bevel gives me an exponential amount of ngons.
This 'section' of the project alone has 17 sections, 11k vertices; 3.4k vertices around the perimeter. That would be 3.4 Thousand 'fixes' to return them to quads. Not worth it to repair the 2 faces that are backwards.
The entire project, all 3:
1 - 11k verts - 1 flipped face
2 - 6k verts - 1 flipped face
3 - 17k - 12 flipped faces.
None of the flipped faces existed before the Join. (Or rather, they were 'repaired' and checked before the join).
I can recreate the issue with a single plane, subdivided for max verts and get the same issue without every altering the shape.
Other suggestions?
Geometry editor can select individual faces (or edge-loops or whole object). Make sure it's on 'drag select' and 'polygon select' and you can then click on an individual face - geometry editing - flip normals on selected polys. To select multiple separate faces, hold down ctrl when clicking to add to selection (and hold down alt when clicking to deselect).
(I'd do screenshots but I don't have DS on the laptop).
The microedge is a great idea, but will not work in my case.
Because everything else has failed, what I have now is 80 individual sections. The bevel gives me an exponential amount of ngons. Not worth it.
Other suggestions?
I will give that a shot. It may take a while to give you a respone.
Will this alter the UV?
Since I still need to select my vgroups for rigging, should this be done After my groups are selected as an All-In-One fix during rigging?
This one's a mindboggler -- Looking forward to more in this thread, and your eventual solution...
I have theories based on what can be deciphered from your individual posts, but too many conflicting variables.
I'd say go with Silent Winter's post regarding Daz Studio's Geometry Editor, since you are 100% sure you have no errors in Blender with your modeling, normals, or approach to the project.
I will state one stipulation; The OBJ file format is a multi-object auto-join format, so, if that is part of what you are trying to achieve, you can eliminate the front-back join in Blender.
Good luck, I wish to see you succeed in an import that yields no flipped faces in your mesh/meshes.
This one is definitely a head-scratcher...
That looks like it took care of the problem of the flipped faces. Of course, back in blender, it now shows as 'flipped'.
I will have to assume that my safest bet is to finish my UV, select my groups (edited), Join into my OBJ, and do the final clean and rig in DAZ.
Does that sound about right??
Please say yes. Please say yes. Please say yes. Please say yes. Please say yes. Please say yes. Please say yes.
I won't say ZERO errors. I am not an expert by any means. But doing a dummy test with a single subdivided plane was eye opening.
I, too, am looking forward to finishing this 6 month long project.
Since this is my first, I swing between, "Not bad for a beginner" and "You MORON!". It's frustrating and fun and humiliating and exciting.
And I want to play. :->
That did the trick. Thank you so much. Not any closer to understanding why this is happening but at least I can get out of second gear.
Thank you, Thank you, Thank you.
Onward! I hope.
Where are your verts on the hypotenuse edge? Are those quads, or tris?
They are all quads.
yes
using the geometry editor to flip normals shouldn't affect anything other than the normal direction (so uvs are ok, rigging, etc - I'd do it before rigging though and try a test-render)
Thank you. Thank you. Thank you.
I can not thank you enough!!!
I just got bit by this. I had been following this thread and reminded myself to check really thoroughly the next time I import an obj to use the transfer utility and sure enough, two flipped faces. No big deal, but seriously... broken obj import?
Yay!! But not.
The Geometry editor took care of the flipped faces, so all of my faces look great in Wire Frame.
Now, I'm going to ask the stupid question that I don't want to ask, but is, at this point, needed.
Wireframe shows all faces are good.
Texture Shaded shows me flipped faces.
Cartoon Shaded shows all faces are good.
So my question is... Am I retarded?
Because I feel a little retareded right now.
Why is this happening???
What is going on???
Wireframe Shaded, Wire Texture Shaded and Cartoon Shaded are fine.
Smooth Shaded and Texture Shaded show "flipped faces"? "holes"?? "My Spirit Dying"??
All renders are fine.
I'm starting to feel a little crazy.
Any thoughts?
I don't think Wireframe Shaded, Wire Texture Shaded, nor Cartoon Shaded even use normals, do they?
I would have to assume Yes. They all need a surface to project onto.
Those are not necessarily flipped faces, those look like shading issues. Check if those polys are n-gons, you might need to add an edge to each poly to split them into two quads or a quad and a triangle.
Check for concaved polygons.
Zero n-gons. Everything is quads. Shading issues would be a welcome change, though.
I will try this one (once I look it up). I'll get back to you.
Basically, look for polygons that look like they are bent or have a crease. If the plane of a polygon is not flat, it can cause some ugly artifacts.
Since I have to go back several steps, to Pre-Join, to check the concave, a quick question:
Can Joining object create concaved polygons? Because pre-Join, these issues are not there.
With each Join, each additional step, these 'brain busters" make an appearance when they weren't there before Join.
So went back to prejoin (folder 3).
Deleted my Back collection (17)
Re flattened my Front collection on the Z
Duplicated my Front collection, moved to -.2
Exported each individually - Clean
Joined: Front Clean, Back Dirty.
AHHHHHHHHHahahahahah!!!
CORRECTION:
Everything is clean UNTIL I flip the faces on the back side, before exporting to obj.
Ok, it's looking like this sits squarely in the Blender forum. I'm going to take this to that forum and brave the "did you look on Google" comments for while. I will, hopefully, be back with an answer.
That would make your initial Q correct.
After making sure the front was good, I copied and flipped faces on the back. Then exported.
All good, right??
Blender always shows a clean flip, but Daz shows otherwise, so.....
I'll be back.