I noticed that Z Remesher can run into problems with low poly objects that have been build from scratch with Z Modeler. Please see below screenshots.
Sorry theer is a typo in image 1 , I meant Q cube , not C cube.
OK, what you’re seeing here are the limitations of the auto-retopology process, not really a glitch necessarily. It’s actually taken ZRemesher a while to be able to achieve results as good as you’ve gotten there.
No auto-retopology process can make as good a decision as a human as to how to perfectly draw lines along edges in highly optimal fashion. There is no magic button for this yet. If you require this kind of topology you will have to build it yourself and work upwards from a low poly base, or manually re-topologize it.
That said, ZRemesher is getting pretty good at it. It depends on the complexity of your mesh, but with reasonable expectations and a bit of elbow grease you can get really good HS results with ZRemesher.
Further notes collapsed below.
To correct your scenario a bit...(click to read)
…you generally wouldn’t use ZRemesher to add polygons in your situation where you have nice clean low poly geometry. You would subdivide it, possibly after adding additional loops to the base to ensure reasonably well distributed, un-stretched polygons. You might also Dynamesh it to enable quick sculpting, if you were willing to abandon your topology.
The more common scenario with ZRemesher...(click to read)
is you’ve been working in a re-mesh heavy process, maybe at medium-high poly density, and you would like to use ZRemesher to simplify your geometry into a cleaner, lower poly form for export purposes, or to work with some of ZBrush’s other features.
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You’ve already discovered that polygroups can be extremely helpful in helping ZRemesher make good decisions about where to draw hard edges. When working for Hard Surface, try to maintain separate polygroups on the planes of your hard surface portions.
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Crease tags are usually the magic ticket though. If you can get well defined creasing onto the right edges of your object, this can significantly improve results from ZRemesher with the “Keep Creases” option. These can be used to have ZRemesher respect those edges through multiple re-meshes. Mostly.
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There will still be clean up work. When simplifying HS, I try to reduce in a series of steps, correcting issues as they pop up. ZModeler can be used to make minor correction, particularly with the Point > Stitch function. If you see a flaw crop on on an edge, you can usually stitch the points back together well enough to repair the edge, and send it through ZRemesher again.
Eventually ZRemesher will reach a limit beyond which it can no longer reduce efficiently. If you require even more optimized geometry, you would have to simplify the rest manually.
Thanks Spyndel. I will definitely look into the keep creases option. I agree, Z Remesher has gotten much better with the
last upgrade and works amazingly well with organic shapes. I figured out how to get a perfect z remesh on that hardsurface shape however. It looks to me as if Z Remesher gets confused when the Keep Polygroup option is on.
The steps :
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Subdivide once to get the Frame Mesh operation in the Stroke menu to work properly on the caps. ( It seems the stroke function needs at least 3 points to create a curve. )
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in Z Remesher turn off Keep Groups, set curve strength to 100.
If you keep the Keep Groups option on it will “destroy” the remesh ( See the shape in the middle )
It’s interesting that the frame mesh strokes which produce a perfect remesh come from the same polygroups that destroy the remesh 
Please post un-cropped images of your interface when reporting suspected problems. You never know what information is going to be relevant to an issue.
Ok, a last one, from left to right z remeshed with keep groups on, keep creases and detect edges on and to the right the successful remesh with the strokes / curves strength 100 option. So for this particular shape, and my guess is , for other rectangular shapes as well, the stroke option is the way to go.
To your question, I am adding polys with z remesher to get evenly divided geo for further subdivision. Is there a better way to achieve this ?
Thanks again for the great tips and I hope this helps to improve z remesher.
Yes, I addressed this in my previous post. This would be another case of using a tool outside of its intended sweet spot. Generally to add geometry to nice clean low poly geometry you would subdivide it (see earlier post for notes on smoothing and hard edges). As we’ve established, ZRemesher has limitations, and is not a precise tool for subdividing geometry-- at least not as a first resort. Most often, it is a tool used for simplifying geometry.
Yet clean, low poly hard surface geometry can be very useful, and you’d generally like to preserve it if possible. Subdividing, with creased geometry if necessary, will accurately preserve the shape, polygroups, and hard edges perfectly without the trial and error or form shifts associated with ZRemesher.
It may be necessary to add additional edge loops to your base level geometry to reshape the polygons and keep them square-ish shaped at higher levels of subdivision to avoid distortion when sculpting or painting.
If you wish to quickly transition to a high poly/re-mesh heavy workflow process, you can use Dynamesh to quickly create surfaces adequate for sculpting. Because this changes the topology to something less deliberate, Dynamesh can only preserve the general locations of polygroups. Their borders will become less defined. This still gives you decent tools to be able to simply the geometry again with ZRemesher, but if you require very specific topology, as you might with hard surface work, you have to factor this into the decision to retopologize.
Oh boy, that’s embarrassing ! ( Using old Z Brush version ). And lo and behold, after updating z remesher is giving better results with keep creases on , even though the stroke option still seems to be the best. I hope I didn’t waste too much of your time, and it certainly was worth it for me as I learned a lot from you , and also figured out a good way for my z remeshing ! ( Which I still prefer over simple subdividing which will lead to much more variations in the density of the mesh ).