I am trying to teach myself Blender and I have got to grips with straight model shapes, animating and generally using Blender but I have come across a strange thing that has happened when I cut something out of an object, below I have cut a hexagon out of a larger hexagon and it looks fine in Blender and Substance Painter but when I put it in GG I get this below.



Can anyone Help

Andrew...

You cant just cut a shape out of an object, you need to create and join the vertices, if you just cut the shape it creates a plane with no edges linking the vertices in the corners, blender can read that types of geometry so it looks fine, but a game engine must have vertices and edge to render, and if it has more than 4 vertices it will warp..


What you need to do is look at each face, if it has more than 4 vertices then you need to create edge lines between vertices to create 2 or more faces with 4 or less vertices, to do that simply select a loose vertice with right click, then shift+right click another vertice and press j.

@Belidos I am not sure what you mean by joining loose vertices together but as you can see below Blender is saying that it has all the Vert's, Edges and Faces that it needs and no extras. It is showing that the model has 24 verts, 40 edges and 16 faces.



I thought that when cut a shape out of another shape that it filled in all the necessary poly's for you which it does seem to do as I can select them.

I have added the .obj file if you don't mind having a look as this is bugging me.

Thanks

Andrew...

Take a look at the first picture below... see inside each the red circles you have two vertexes defining the shape of the corner? Those need to be joined together with an edge to anchor the position of the vertexes (see picture 2) , otherwise when it goes into a game engine it will straighten the line causing the geometry issue you have.

Basically yhe rule of thumb is thst each face needs a maximum of 4 vertexes otherwise it will distort.

To do that, switch to edit mode, change to vertex select, right click oneofthe dots, then shift+right click the second, then press J, repeat for all the parts that look like that.

Basically game guru (and most game engines) are less tolerant of ngons - faces with more than 4 sides - than Blender and substance painter etc.

What Belidos is suggesting will work but the quick and dirty way of solving this problem is just to apply a triangulate modifier to your model. And either apply it or make sure the exporter is set to 'apply modifiers.' That will work in the vast majority of cases.

Not sure about blender but you can select al vertices and weld ,that will snap them together

(Edit I think that’s just what Beldios just said)

Dave

True, you can use a triangulate modifier, however that will create extra geometry and faces, plus when creating models for game engines it's best to try to keep to quads as much as possible because most game engines automatically convert quads to triangles when rendering them, and when you already have triangles in a model it can warp them, especially when you have a large flat face cut into triangles.

Personally i would stick to doing it manually, it's cleaner and less chance of causing issues.

I am sorry everybody but none of this works, I have tried changing everything to ngons and tris but neither of these worked. I have also tried exporting with modifiers selected and still the same.

I just don't understand what is wrong and I have searched the web for a solution. I have learned quite a lot doing so but not how to fix this problem.

I even wondered if it was because my normals were out but when I checked them they were all facing the right way.

<Edit>
I just had an Idea, I wondered if it was because of the UV Map so I went to that and had a look at what I could do, one of the things was Remove Doubles UV under Weld so I did this and voila it is now perfect.

The image below shows what I mean.

The Entity on the left is after I changed the faces to quads and the Entity on the right is after I then changed the UV Map as described above.


Thanks, everyone for your help.

Andrew...

It's got to be something else you did, because the UV map will not effect the geometry of a mode other than where the texture shows on the model, it's physically impossible.

Actually, i just noticed ...

Remove doubles isn't anything to do with UV maps, what it does is merges any vertexes on the model that overlap each other. It may be that the boolean you used created extra geometry between loose vertexes, and that's why it fixed it.

But the odd thing there is what i showed you previously worked 100% exactly as i did it for me on your model maybe converting it to obj then importing it fixed some of the broken geometry, next time might be better off supplying the .blend file rather than an exported model, that way we can see clearer.

Give me a shout any time if you need any more help with blender.

P.S. With regards to modifiers ... ALWAYS apply them before exporting, the tick box for auto applying modifiers doesn't always work, always make sure you physically apply them. Also Some game engines don't like Blenders boolean modifier, even after it has been applied, no idea why, but it's a common complaint.

@Belidos, I know for sure that it was the Remove Doubles because I checked to see if I could replicate it and I could, I assumed that it was a UV Map thing because I found it under the UV Map menu. You might be right about exporting to .obj first, I will send the .blend next time.

Thanks for the offer of help in the future, you might regret that lol.

Andrew...

Ah i see what you mean, yeah it's in the UV menu but it's not really doing anything to the UV's, it's a way of removing the double vertexes from the model by selecting them on the UV. To access that function without going to the UV window is by highlighting everything in your model by pressing A (in edit mode), then pressing W (this brings up the specials menu), and then pressing R to remove doubles.

You know Belidos, I agree with you that anything you do in the UV Map should not affect the look of the model except how the texture looks on it. Saying this the Remove Doubles that you have pointed out is completely different to the one in the UV Map menu.

The one in the Specials Menu, 'Removes Duplicate Vertices'.

The one in the UV Map Menu - Weld/Align is called Removes Duplicate UV and it says 'Selected Vertices that are in a radius of each other are Welded together'.

I have done quite a few tests with this because I agree with you it should not be happening. I have even done a test where I changed all the faces to quads or tris before I created the UV Map and when this is done everything is just fine, it is only when the UV Map is created before the changes are made to the faces that there is a problem and I have to 'Remove Doubles UV' on the UV Map.

Andrew...

That's really odd.