need better topology

[rpmaguire]

Can anyone inform me on how to better topologize this mesh?

Thanks,
Ryan

[SpookyMunky]

Hi Ryan, usually for something like this I would start out with a cylinder that has enough polys to contain the holes I want without deforming the surrounding polys too severely.. hmm I made a pic that better explains it I hope . . .



I got a bit lazy and used the MX_Roundish addon to create a base shape for the holes, you can find it here.. http://maxfoxlab.com/mx_roundish.html .. its very handy

Don't use my poly layout as a guide too much, usually I'd spend some time figuring out exactly how many edge loops I wanted and where to add them etc.. just kinda guestimated for this and the larger holes didnt come out as nice as Id want I guess hehe.

One trick you can use for an object like this is to leave the pie section flat (ignore step..2 or whatever hehe, shoulda numbered them) and use a deformer on the merged result to raise the center.. like if you use a cylinder where all the points match up close enough to your mesh as a cage deformer you can sometimes get decent (though slow) results.. that way you can adjust the shape of the holes on the master object without the annoyance of having to make sure the points you are moving still line up with the conical shape etc.

I hope this helps, usually I just keep experimenting till I find something that works.. no shame in failed attempts before I find a poly flow that works

Edit: Looking at the image again I can see why I don't like the larger holes.. the top and bottom (inner and outer) edges of the holes have 3 cuts whereas the sides only have 2... doh!, best to try and avoid that kind of thing usually ( or it could just be my ocd hehe ) .. sorry

[fabilabo]

hahah nice job, finally you can send him the object you made

[Letterbox]

Can anyone inform me on how to better topologize this mesh?

Thanks,
Ryan

Look at the hole you have at the top of the disk in the left image. There is a vertex there that does not connect to anywhere. Select that triangle polygon above the circle and then right click select 'subdivide polygon', then use the parameter "X", that should help some with the pinching that you can see in the right image.

Look at the large circles again, see that at the top of the circle you -do- connect that vertex, as said above.

After that, you could loop select the circle and bevel it (a small amount with 2-3? loops), that'll keep it's shape when sub-divided.

[SpookyMunky]

Look at the hole you have at the top of the disk in the left image. There is a vertex there that does not connect to anywhere. Select that triangle polygon above the circle and then right click select 'subdivide polygon', then use the parameter "X", that should help some with the pinching that you can see in the right image.

Look at the large circles again, see that at the top of the circle you -do- connect that vertex, as said above.

After that, you could loop select the circle and bevel it (a small amount with 2-3? loops), that'll keep it's shape when sub-divided.

vertex that does not connect to anywhere ?.. I guess you mean the asteroids quad ? ( I forget the proper name, non-uniform ? hehe ) splitting that won't fix the pinching issue, it will fix uvs, but for subdiv smoothing usually it can make pinches more pronounced in my experience, though since it part of a star connected to the point it might not make much difference. There are a few annoying rules with xsi subds (and most Catmull-Clark / similar based subd systems that date back to the 70s/80s hehe) , mainly just dont use tris or have points with more than 4 polygons connected to them near a hard edge / crease / anything that deforms... way I see it .. also in xsi is best to try and keep subdivisions uniform if you are going to texture.. very annoying

Your 2nd suggestion.. he has enough cuts inside the holes, why the mesh actually has spherical holes. Adding external loops without adding more polys overall will make it look worse imho. By all rights the mesh should be hexagonal, its impressive that its kinda round when subdivided, without the extra polys in place I cant see a way of getting rid of the subds natural urge to try and think they should be part of a hexagon around the holes.. there is nothing between them and their neighbours saying "no!.. we are a cylinder !".... or something

edit: sorry Letterbox, am in a grumpy mood today for some reason... no excuse for not being nice.. arr

[Daniel Brassard]

The pinch is created by polygon's triangles that are not on the same plane, i.e there is an angle between the polygon's triangles (i.e the polygon is not completely flat).

You can try to fix this by selecting the polygon(s) and scaling the y to zero in local mode for each area where you notice a pinch or moving the middle vertex until the polygon's triangles are perfectly aligned (flat) i.e their normals are equal to each other.

[SpookyMunky]

Maybe you are right, I dont see it though, to my eyes it looks like wasted effort though.. I have lost too many hours trying to smooth out dents in subd hehe... its a waste of time .. I like to think I can look at a mesh now and say really not worth it, sure this is one of those times . Maybe I am jaded.. considering that image took me 5mins to make tho.. I feel comfortable with me start again argument

I can throw together the same mesh he has for you if you want to prove me wrong, though really it should be the challengers job

Edit: again am not saying the mesh is beyond fixing, just better to teach someone to start again surely ? and show them ... I never had someone tell me how important and time saving planning was hehe


edit2: even if it did work.. what exactly is the form of modelling you are you trying to encourage ?

[Letterbox]

The pinch is created by polygon's triangles that are not on the same plane, i.e there is an angle between the polygon's triangles (i.e the polygon is not completely flat).

You can try to fix this by selecting the polygon(s) and scaling the y to zero in local mode for each area where you notice a pinch or moving the middle vertex until the polygon's triangles are perfectly aligned (flat) i.e their normals are equal to each other.

Exactly the poly(s) i was referring to, thanks Daniel. ;)

[origin]

Yes op listen to spooky,
you need a solid foundation in subd modelling, getting the principles of it like inserting holes, poly flow etc, not fixing bugs on bad model.

[Daniel Brassard]

Can anyone inform me on how to better topologize this mesh?

Thanks,
Ryan

Like Origin and SpookyMonkey said before, good planning and efficient modeling workflow is the key to avoid these problems in the first place.

There used to be some good articles concerning efficient modeling to prepare your mesh for subdivision on SUbdivisionModeling.com. Unfortunately, this site is no longer available. Fortunately some of the most useful articles have been saved by members and posted on the web.

http://web.archive.org/web/201101010129 ... .php?t=907

http://web.archive.org/web/201101010135 ... php?t=8000

If you notice SpookyMonkey modeling info, his hole is not on the edge of the original low-poly mesh disk but at the center, where flat polys are encountered. By doing so, he avoid the co-planar issue entirely.

Turning the 8-side hole 45 degrees so that the upper and lower edge are parallel to the main disk will also help you maintain efficient quads and avoid unnecessary triangulation.

I invite you to read the two threads i have posted above, their is a lot of nuggets of wisdom in their to improve efficient low-poly modeling and subdivision.

Like SpookyMonkey said, sometime you will have to recognize when a mesh can be saved, when efficient re-topology is needed and when a totally new mesh is necessary.

Cheers!

[Daniel Brassard]

To illustrate my point above, I have provided a low-poly division modeling sketch (I assumed here that you wanted as low a mesh as possible and that the 8-side hole was a requirement).

Nothing but quads in this scenario. Notice the location and orientation of the holes in the sketch. Some beveling for the holes and final adjustment as per SpookyMonkey earlier response will prepare the mesh for subdivision.

In fact, if you compare this with SpookyMonkey mesh, you will see the similitude.

Cheers!

[rpmaguire]

Thanks allot for the replies everyone!
never knew about mx roundish... very handy!
This has been very helpful thank you.

[SpookyMunky]

rock on dude .. to my ocd eyes it looks better, might still notice some pinching though.. depends how sharp the cut needs to be.. my pic prolly wasnt that clear, after roundish I extruded the same polys and using local scale created a ring
hmm, sorry if this makes no sense .. for me its just a buffer that you can smooth so the surrounding polys arent pulled so much towards the large holes

cheers for not following my poly layout.. I admit it was bad