[Solved] polygons missing in 3Dcoat per pixel import from blender obj/fbx

[Ascend204]

hey I've got a question, for multiple models that I've made in blender there seem to be missing polygon to where i can only see half of the model, not only that but when i draw on one part of the model it will also automatically draw on other parts of the model in random places. any1 know a fix? I am extremely new to 3Dcoat and testing out the trial version, really like the software but I can't work with the models that I've made. I am also not extremely well experienced with blender but i do believe i have correctly uv unwrapped the model.

https://imgur.com/a/06gc0L5

 

[Fluffy]

3 hours ago, Ascend204 said:

hey I've got a question, for multiple models that I've made in blender there seem to be missing polygon to where i can only see half of the model, not only that but when i draw on one part of the model it will also automatically draw on other parts of the model in random places. any1 know a fix? I am extremely new to 3Dcoat and testing out the trial version, really like the software but I can't work with the models that I've made. I am also not extremely well experienced with blender but i do believe i have correctly uv unwrapped the model.

https://imgur.com/a/06gc0L5

 

It's hard to tell from just those two images but your missing polygon problem could just be down to single-sided polygons.  The easiest way to check if that's the case is to try turning off Backface Culling in the View menu.

As for the issue with brush strokes, etc. appearing in multiple random places one possible explanation is overlapping UV islands which you should be able to see if you turn on the Wireframe option in the Texture Editor window.

If you're unsure if the model has been unwrapped correctly in Blender you could always unwrap it again in 3D Coat to see if that fixes the issue.  You can either adjust the UVs on the paint model directly in the UV room or use the Take mesh from Paint room option in the Mesh menu of the Retopo room to import the model there

and the Update Paint Mesh with Retopo Mesh option in the Bake menu to apply the changes to the model in the Paint room when you're done UV unwrapping.

(Using the UV room works best if your model already has textures applied since changes to the UVs there also affect the textures whereas if you make the changes in the Retopo room and then update the model in the Paint room only the UVs will be affected)

[Ascend204]

18 hours ago, Fluffy said:

It's hard to tell from just those two images but your missing polygon problem could just be down to single-sided polygons.  The easiest way to check if that's the case is to try turning off Backface Culling in the View menu.

As for the issue with brush strokes, etc. appearing in multiple random places one possible explanation is overlapping UV islands which you should be able to see if you turn on the Wireframe option in the Texture Editor window.

If you're unsure if the model has been unwrapped correctly in Blender you could always unwrap it again in 3D Coat to see if that fixes the issue.  You can either adjust the UVs on the paint model directly in the UV room or use the Take mesh from Paint room option in the Mesh menu of the Retopo room to import the model there

and the Update Paint Mesh with Retopo Mesh option in the Bake menu to apply the changes to the model in the Paint room when you're done UV unwrapping.

(Using the UV room works best if your model already has textures applied since changes to the UVs there also affect the textures whereas if you make the changes in the Retopo room and then update the model in the Paint room only the UVs will be affected)

thank you for sharing, indeed turning off backface culling worked and i can see the entire model now from all sides (however the ones that previously did not show do seem to look a bit darker then the rest of the model. do you know of any way to fix single sided polygons and make them double sided? is it something I've done wrong in blender or does it have to do with blender to 3Dcoat workflow? if its in blender would you be able to explain the fix/send a tutorial if possible, i would really like to know!

[Fluffy]

37 minutes ago, Ascend204 said:

thank you for sharing, indeed turning off backface culling worked and i can see the entire model now from all sides (however the ones that previously did not show do seem to look a bit darker then the rest of the model. do you know of any way to fix single sided polygons and make them double sided? is it something I've done wrong in blender or does it have to do with blender to 3Dcoat workflow? if its in blender would you be able to explain the fix/send a tutorial if possible, i would really like to know!

The reasons that the back-faces on the polygons look darker in comparison to the front-faces is because the back-faces are in shadow since they're facing inward rather than towards the light source.

Single-sided polygons aren't exactly something you can "fix" since making them double-sided is a process that occurs in whatever renderer/platform you intend to use the final model in (some will support double-sided faces and some won't).

More importantly making the polygons double-sided won't allow you to add textures to both sides, whatever textures are on the front side of the polygon will appear mirrored on the back face since both sides share the same UV space.

In order to make polygons which are double-sided and have the ability to texture both sides independently you'll need to add additional polygons to the model.  I don't really use Blender but here's a couple of ways you can do it via the Retopo room in 3D Coat.

First you'll need to use the "Take mesh from Paint room" option (see previous post) or just import a copy of your model to the retopo room.  Once you have your model in the Retopo room, select all the faces using the Select All Faces button in the Poly Groups panel

 

If you want the faces to have volume/thickness then you can use the Shell tool, otherwise use the Flip Faces tool (both are located in the Selected section of the Tools panel on the left hand side)

If you use the Shell tool then you'll need to UV unwrap the newly created faces and then use the Update Paint Mesh with Retopo Mesh option (see previous post) to replace your original model in the Paint room whereas if you use the Flip Faces tool all you need to do is use the Retopo > Per Pixel Painting (no baking) option (see below) in the Bake menu to import the flipped version of your model into the Paint room alongside the original version (don't forget to rename your UV Set so you don't end up with multiple UV sets with identical names).  Once you have the flipped version of your model in the Paint room alongside the original version you can just swap between the two UV sets depending on which side of the faces you wish to work on.