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AutoRetopo not working on some models


andre3000
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Hello everyone,

I am new to 3dcoat and am currently using the demo version. Sculpting is amazing but autoretopo isn't working on all the models, some very simples ones made of spheres don't turn into polymesh spheres, instead I get nothing.

Can someone help me?

3dcoat auto retopo problems sculpting.PNG

3dcoat auto retopo problems retopo options.PNG

3dcoat auto retopo problems retopo normal projection.PNG

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Rules of Thumb for using Auto-Retopo successfully:

1) Keep parts separate on their own layer, when feasible.

2) Create a lower resolution Dummy copy and Fill or smooth surface details that you do not geometry to represent (ie. Normal Map details).

3) Try a little higher poly count than you think you need. Going too low can make Auto-Retopo fail.

4) Before running Auto-Retopo, it is a good idea to RMB click the layer > FILL VOIDS....in case it has any small internal pockets. These can cause issues with Auto-Retopo.

5) If the model is Symmetrical, enable Symmetry before running Auto-Retopo

5) If the first attempt doesn't yield satisfactory results, retry and add some stroke guides to help tell 3D Coat how you want your topology to flow

 

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A little more information.

3 layers, 3 separate autopos.

My start from settings. generally I get good results from these settings and adjust as needed. Not the amount of polygons, that is per model need.

Turn off voxelize before quadrangulation. Not needed, you are in voxel mode. This might be causing a problem as well. You use that setting only if you are in surface mode.

---------------------------------------------------------------------------------------------------------------------------------

Last picture... I merged all the layers together... Created a dummy lower voxel count model. ran smooth all  to smooth out some of the piping rings according to AbnRanger's advice.

I ran the autopo routine. It worked well. Autopo can get confused if to many finer details are present in the model like AbnRanger said.

Next you hide or delete the dummy copy no longer needed.

Unhide the original model for baking.

Autopo works, just takes some practice for you to figure out how to work it.... :D

settings.JPG

Capture66.PNG

second.PNG

Edited by digman
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7 minutes ago, andre3000 said:

How do you manage to retopo that network or strings?!

This is what I'm getting with those same settings.

I attached the project in case there is some obvious settings that's unpleasant to the retopo thing.

3d coat retopo missing something.PNG

organic ground.7z

You have to simplify things for an algorithm. That's the case no matter what app you might use, that has some kind of Auto-Retopo. You are trying to throw too much at it, at once. All those ribs/details are increasing the amount of complexity and therefore increasing the degree of difficulty. It can probably handle each part, ok, but not at 1000 polys for the whole thing. Did you watch the video posted above? It mentions/demonstrates these things.

If all of that is on one layer, switch to Surface mode (if it's not already) > go to the GEOMETRY menu (Sculpt Room) > OBJECTIFY (SEPARATE). Now, on each individual layer, click SMOOTH ALL at the bottom of the tool panel > run Auto-Retopo. Maybe 1000 per object, if not more.

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I looked at the file. 

Your voxel count was way too low when created the more complicated pieces. You have tiny floating pieces and other problems. The model you shown in your last post was only 99,000 voxel / triangles, way too low to capture those kind of details and will also cause autopo to fail as you do not have enough voxel resolution. It only appears better in the screen shot because the shader is doing most of the work. When we talk about creating a reduced voxel count dummy for autopo, It would be more like going from 6 million voxels to 1 million or 2 million.

 I found a few other funny glitches too. I would ditch this file. I exported the models out just so I could test on a  clean 3DC scene.

Voxels are 3D pixels, just like a 2D photograph you need enough pixels to capture the detail.  

I did repair the models enough to run autopo. They did need some fixing up too..

The test were successful. Now I know the voxel structure is sound. I could go back and re-run the autopo with a lower polygon amount though you always need enough for the routine to cover the model / models effectively. 

Depending up how much smaller detail there is you can increase or decrease the capture detail amount. Watch  AbnRanger's video carefully and read my posting again. 

Remember in my first posting... The 1000 polygon amount in the autopo panel was for my model. You have to set this number according to your model.

Start a new 3DC file and create voxel models according to the amount of voxels you need to create the detail needed. If needed increase the voxel resolution of the voxel  layers shown in the picture. 

If you create your voxel model or surface mode model correctly plus follow the guidelines by AbnRanger and myself, in most cases autopo will work and fairly quickly too. 

 

fixed.PNG

Capture69.PNG

Edited by digman
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WOW! This is clean polymesh, @digman!

I followed your advise and exported the volumes then new then import then upped the resolution of that big Gigerish blobby thing by 4x and then lost myself resculpting it - it's nice now!

Then I tried healing it using "fill voids" and "close invisible hulls" - is that what you used to repair the geometry? how do you visualize islands and problem areas?

I autoretopo-ed this one and it's not working, I'm getting no polygons out of the 10K budget I gave it in the retopo settings. The other objects no retopo fine in auto mode! It's all in the split :)

I just went through the video @AbnRanger, I want to avoid manual work when not necessary. The problem was many problems in the voxel  and disconnected islands rather than the complexity. I noticed that if you feed autoretopo one volume made of separate islands it chokes hard during the making seamless edges phase.

Questions:

  1. are there better ways to reparent volumes than RMB>change parent?
  2. does export to fbx require the volumes to be retopo-ed? or surface work? When I click on V and turn to S they are paintable in the paint room, just very slow. 
  3. do you use macros to automate the split volumes + autoretopo each split?
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I ran each layer on it's own, no problem with non-connected objects on the same layer.

On the blobby object. Yes fill voids and if necessary close invisible hulls. I also zoomed around the model looking in the nooks and crannies. I filled in some very deep crevices with walls almost abutting each other due to the bobby nature of the object.They were not really real details but just created as you were having your first go at sculpting.  3DC would have to figure out how to run the edge flow to those deep crevices making polygons to try and cover them. Those tend give autopo a hard time. Remember autopo follows the curvature of a model and you are giving it too much to handle. The deep crevice walls being so close together that you could get weird snapping of the vertices too. We are free to sculpt in 3DC but still have to create good topology for the creation of the polygon retopo mesh. If someone was hand modelling a bobbly object those type of crevices would not be created as it would be poor topology work. I am not saying you can not have crevices but these would not be good ones.

Invisible hulls work but will create areas that need some smoothing or sculpt repair. It will create zaggy rough voxels on the surface plus not very thick in areas that it repaired. Can not leave them like that. Close invisible hulls is used on really dirty meshes. You want to avoid if possible this kind of messy voxel work that creates the need for using the tool. Do not worry you are learning fast... I also created a lower voxel count dummy version and smoothed that a couple of times.   

If 3DC is having a hard time when running the autopo, most of the time something is be wrong with the object. I ran all 4 layers one at time and finished autopo fairly quickly on each layer, not hanging anywhere along the way.

I ran bad meshes in Mudbox's autopo and it crashes the whole program, so not a problem alone with 3DC. 

Just to let you know , I had to keep looking for the errors a couple of times, I had two failures on the bobbly object, till I found and corrected them. 3rd time was the charm.

Edited by digman
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I chased down weird glitches, they were all inside the giger thing, some floating islands, some scrambled polys and even areas that were not drawn so I passed all that mess with a strong smooth brush and voila! Thanks for the help, it makes more sense now and I'll be able to do it by myself.

All is not rosy though, see how the autoretopo keeps vertices inside the volume so the nice crested profile is lost. Short of moving vertices by hand (and move tool behave very strangely caving in vertices instead of floating them on the volume's surface) is there a way of sorting this stuff out? (I'm on an i7 920 from 8 years ago so retopo is very slow, that's why I haven't tried 10 gazilion settings to figure it all out)

3d coat retopo missing detail.PNG

 

the final result with blueberry jam on top

 

3d coat finally it works.PNG

 

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8 hours ago, andre3000 said:

I chased down weird glitches, they were all inside the giger thing, some floating islands, some scrambled polys and even areas that were not drawn so I passed all that mess with a strong smooth brush and voila! Thanks for the help, it makes more sense now and I'll be able to do it by myself.

All is not rosy though, see how the autoretopo keeps vertices inside the volume so the nice crested profile is lost. Short of moving vertices by hand (and move tool behave very strangely caving in vertices instead of floating them on the volume's surface) is there a way of sorting this stuff out? (I'm on an i7 920 from 8 years ago so retopo is very slow, that's why I haven't tried 10 gazilion settings to figure it all out)

Great! You are learning quickly how to create a good model and what to avoid for Autopo. Keep at it...:D

All autopo routines do their best to cover the topology with the amount of polygons asked for but none of them are perfect and have a harder time on complicated curvature topology to getting it just right in all areas. When you select the number of polygons from the Autopo panel to create the retopo mesh and if 3DC created less than you ask for, run  Autopo again. This time select a higher polygon count to get what you need. I know it is a pain doing so on your computer but after awhile you will get the hang of the autopo and kinda know how many polygons to ask for according to your model structure.  Whenever sculpting a model in 3DC knowing that you are going to use autopo ask yourself this question.

How will autopo handle this area... This of course comes through more experience in using the autopo routine. 

I am not covering placing guide curves, one step at a time.

Or:

Subdivde the retopo mesh in the retopo room. Yes your will increase the polygon count 4 times but the areas in question will get covered better. Do this if you are not worried about the polygon count. 

Side note: Check at the bottom of the GUI to see how many polygons were really created after Autopo is completed.

Edited by digman
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I get a good sense of polycount now, I crank it up then polyreduce in maya when I feel like it... which I only do when the game runs below 90 fps which hasn't happened yet on this 970.

By the way is there a polyreduce in retopo? I could only find a brush to do that manually.

Also I'm surprised there even are islands, some are 3 polys, very small and I'm lucky I found them. Are there tools to help detect them, or even better remove them below a certain size? W->S->split/objectify has a function like that but that means you have to use split. A system to remove anything below a certain thickness would help a lot.

The big question is, with V->S and painting on S, Is retopo even needed when doing an export?

Edited by andre3000
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