View Full Version : reducing many sided poly to quads?

05-02-2018, 01:39 AM
What's the best approach to reduce the central poly here to quads?

05-02-2018, 04:08 AM
one way >

-make pole
-select nth, in edge mode
-delete edges


05-02-2018, 09:33 AM
That's a really good way to reduce a "pole" type (globe pole-like) situation (especially the use of "N PATTERN"), but in my case I'm wanting something a bit different:

Because of the number of edge points (~47), just using "Make Pole" results in a great number of long skinny triangles. What I'm looking for (and maybe 3 years ago knew how to do semi-efficiently) is a steadily decreasing number of rings of quads (if I keep typing long enough I'll figure it out again). IIRC, Probiner made a number of graphics detailing the principles.

Of course, it's always easiest when the numbers work out to specific multiples, which I also don't remember.

+: someone not too long ago did a neat video about reducing the top of a 'pop can' inwards (that is, after most of the can was modeled) in an all quad manner, but at some point my bookmarks got lost. Sound familiar anybody?

PLUS: if you google "Probiner quads" you will find many images made by same, very very helpful.

05-02-2018, 10:29 AM
uneven numbers on regular objects will never work, unless one add trigons, or additional geometry.

there is quad skin patcher, the plugin, but this also only works on even numbers, not uneven.


05-02-2018, 10:43 AM
You might consider getting rid of most of the "excess" geometry:



Interestingly enough, for this model (which is NOT all quads) the trigons at the crease between the tentacles seem to work better than trying to make them quads. I tried various methods of using quads there, but ended up "pinching" the crease in one way or another, so in this particular case I'd leave them tris. I'd be interested in an expert modeler's opinion, though.


05-02-2018, 11:38 AM
tris can be better

they are not always better
- if the object is deforming heavily (twisting/bending)
- if the object needs to be UV'd. trigons can distort the texture in unwanted ways.

so it's best to avoid them for organic modelling, however, they can be used, depending.

05-02-2018, 01:01 PM
Nice tip erikals..
May not work all the time, but I often use cm_polydivide...

there is also quadskin as erikals mentioned, but I am more comfortable with Cm_polydivide, it consists of three scripts, yielding various results, for making exact symmetric polyflow you may sometimes have to spin edges..if the result isnīt exact sometimes.

05-02-2018, 02:53 PM
yeah, polydivide is nice, a bit faster, still has a problem with uneven number of points, like all other operations
the only way to fix uneven numbers (in general, numbers that cannot be divided by four) is to add trigons or additional polyloops

just adding an example > Quad Skin Patcher


05-02-2018, 05:44 PM
You might consider getting rid of most of the "excess" geometry:
This is matching a RW object, but yes, could certainly be executed better. I'm massively out of practice.

05-02-2018, 07:34 PM
This is matching a RW object, but yes, could certainly be executed better. I'm massively out of practice.

OK, understood - matching real-world definitely makes it tougher for me. In case it helps, here's an all-quad version, starting with a 15-sided disc. The second try went MUCH faster! :)




05-03-2018, 08:59 AM
Thanks for your attention, always educational.

If I were to approach this again, and I probably will, I'd just use a profile and EXTEND along the arms. Tracing in PShop and importing an *.AI was a losing move, my bad. Although the non-functioning of TOGGLE BACKDROP on my system, and the general badness/weakness of the Background Image system in LWM will no doubt make it super aggravating.

05-03-2018, 12:38 PM
Well, I'm trying to get better at subpatch modeling (going through William Vaughan's "Pushing Points" slowly but surely), so it's nice to get a challenge!

RE: Tracing it, that reminds me of a technique that I've used to make subpatch letters which works quite well. I went ahead and used this process on the image you posted in the original post and documented it. As I said, a nice challenge. I hope you don't mind. I should also note that I'm NOT any sort of expert, so experienced modelers may just laugh at this! :)

It definitely might not be close enough to match your real-world object as needed, but the technique has been really useful for me numerous times.

In Modeler you expand the Back view pane to full screen and bring in the Reference image as a backdrop, then use Add Points to add points around the profile with more points at sharper curves, then p to make a polygon. I then use Slice to "complete the strokes" of the letter (e.g. make an edge between the upright and the crossbar of the letter "T", or in this case, separating the tentacles from the core body to form a pentagon). Then "whack up" each tentacle into 6-8 chunks with Knife, putting edges closer where I want sharp turns, in this case at the end of each tentacle. On the center pentagon, use Make Pole, change to Polygon selection (where the polys created by Make Pole will be selected) and Connect to make the "hub". Then use Connect (if you're lucky) or Slice to run a center line down each section of chunks.


Note that the last polygon on each tentacle isn't included, which will end up being a four-point triangle.

After that's complete, I use the Statistics panel ("w") to select all points that only exist in one polygon, and un-select the ones on the corners / tips / sharp edges. Delete the remaining one-poly points, and usually end up with a bunch of quads and tris which can be converted to subpatches.

141515 141516
141517 141518

Then, I use Drag and Stretch to match the subpatches up with the Reference image, using Knife to add edges if needed. In this case, there were enough edges so I didn't need to use Knife. On objects / letters that have sharp corners, I use Stretch to shrink adjacent points down to VERY close to sharp corners on the Reference.


To get the flat front and back, I Extruded it, then selected the front polygons and used "e" (Extender Plus) to "duplicate" those polys, Connect to divide the side polys and flatten the back the same way.

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141524 141525

Taper Constrain to the front, flatten it a bit and texture, resulting in:

141526 141527

141528 141529

05-03-2018, 01:22 PM
Good stuff. :thumbsup:

BTW, re the subject: for any given perimeter with an even number of points, there is a simple grid (ie "flat box") that will match that number of points/edges. Using BRIDGE on sections makes short work of it. And the closer the quad matrix's perimeter resembles the geometry to be matched, the better BRIDGE works.

05-04-2018, 10:59 AM
Well, I tried several "automated" methods (including Bridge) to build the interior edge network, but for me using Slice and Knife (especially the right-click and right-drag functionality on Knife both to cut and move the position, or to move one of the endpoint) is very fast and produces a nice, clean set of interior edges. Bridge creates a very dense interior network, which is where I think you got all the "excess" geometry in your original posted image. By using Knife and then deleting the single-poly points (except on corners and creases), the resulting subpatches are very clean, IMO.

I've attached a 7-minute (with a bit of occasional meandering) MOV file showing this technique on a serif-font capital N, which I think turned out nicely, although I'd do the serifed top and bottom pedestals a little differently next time. I didn't show getting rid of the two remaining trigons at the end of the video: the upper left one was merge polys on the top pair of polys and slice it into two quads, the upper right was bring the two upper points together and weld them.



BTW, the "fiasco" at about 5:50 trying to select two points to be welded was due to the reassignment in LW2018 of the slash ("/") key to be to TOGGLE the selection on or off. For 20+ years I've relied on slash to DROP the current selection and use space-slash-space-slash-space-slash to clear ALL selected points, edges and polys. I think reassigning it to TOGGLE was a really, really bad choice - one of my few changes to the Shortcut Keys in LW2018 was changing it back.


P.S. sorry some of the menu selections (e.g. Connect) were off screen - the screen capture software I use only captures the current window, and I didn't notice the menus were outside of it.

05-04-2018, 02:13 PM
My main error was in using an imported AI spline-- the time savings was negative. Too many points.

On BRIDGE: only to replace the central, large flat poly. QUAD SKIN PATCHER would probably be the proper way to griddify that area. Getting a nice, even distribution of quads is, well, nice.

FWIW, and you certainly don't have to do anything with this, here's the actual original object. It also is curved upwards in the middle. I'm contrasting LW and C4D to improve my grasp of c4d modeling.

05-04-2018, 06:33 PM
OK, thanks for the reference. Here's a 1-hour attempt, most of which was wrestling with the Surface, which *still* isn't right but not sure how to fix it. I'm definitely still struggling with getting what I want with the Principled BSDF surface type. As well, the sides aren't really reflecting your environment, I just used your image as a Textured Environment for the lighting.

Exactly the same technique I documented previously. I don't think the tapering or curvature is quite right, but without side references I just guessed.



05-04-2018, 07:05 PM
A little better.


Time for *other* fun...


05-05-2018, 02:25 PM
For some shapes that isnīt too convoluted, you may get away with using cm loft, works on curves ( sidenote is that you can use polys also for other lofting tasks)
And for MonroePoteet, I wonder if you are not better of using the line pen instead of slice tool?..one have to be careful though and make it snap exactly on any vertex for a "true cut" unlike slice, but you have the advantage of not having to restart the tool between each connection as you have to with the slice tool, and with line pen you can middle mouse click and drag a straight line, and also reference snap to perpendicular lines etc.

05-06-2018, 07:43 AM
The Line Pen tool may be a good fit for completing the strokes, as you said. I tried it, and as mentioned, I have to be quite careful for the "hints" (e.g. "EDGE", "VERTEX", "CENTER", etc.) to show up before clicking to make sure it's "attached" to the existing geometry. Otherwise, I end up with spare edges (sometimes many of them) which are a little time-consuming to remove if I don't notice them right away and do an Undo.

Thanks for the suggestion - I also plan to submit an Enhancement Request to have Slice "reset" (i.e. act as if freshly invoked) with either a right-click or when clicking outside the Views (e.g. in the menu area) as other tools do. Having to restart it for each addition slice within a polygon is a pain - if there's multiple polygons I can click in a "distant" polygon to get it to reset.


05-06-2018, 08:31 AM
Yes..both line pen and slice tool could be enhanced maybe, I have an issue with the slice tool not being able to be constrained straight, while the line pen and middle mouse button and drag do just a straight constrained line, and I can also match up a line to meet another lines endpoint at the side, if I keep dragging with middle mouse, but hover over that endpoint, that will start perpendicular guidline so I can snap the current point in line with the other end point.

And if I am about to snap per vertex..one advice would be to turn of edge or any other snapping option and Only use vertex snap, otherwise there is a risc of snapping towards an edge close by vertex and not actually the vertex itself.

With the line pen, and middle mouse drag and using these guidelines ..it is easy to create walls or a floor plan, unless using lw cad..I do not know of any offset tool though, so you have make up your mind wether or not these lines are the outside or inside of the floor plan or walls, then once the walls/floor is made...you simply bevel it with constrain to get an offset, with the line pen and itīs nice snapping with guidelines..that is easy to do without a grid, the line pen and the grid is needed when you may want to create exact measure.

Otherwise you could use the standard pen tool, but it has no way of having guidelines to create sides exactly snapped in sync, Unless you of course use the grid snap.

05-06-2018, 01:38 PM
Not sure what's up with THIS: selected 32 Edges (from a 'pole') and hitting DELETE (mapped to "REMOVE") only kills the FIRST edge.

+:...seems to be object specific, since CLOSE ALL, make a test cone and experiment works fine.... :mad: :bangwall:

++: overlapping polys. ::sigh::