Dark patches on render

[MartinSax]

Hi all,

I have had this little issue pop up on a particular model of mine.

I have set the settings higher etc, but to no Avail.

Vertex maps etc...are off, i really dont know what the issue could be. ive tried moving and plaing with lights/illumination and quality but nothing seems to help.

I perhaps think it might be because the polygons Might be double sided?...that the only conclusion i can come to, but i really could adjust such a things on a large models like this.

Has anyone encountered this before? LW 2018.

The 2nd images is a basic setup, textures changed to Principled BSDF, i dont think its a texture issue.

M

 

[Sensei]

Are you using UV mapped textures? Such things happens if border around UV island on image is too small.
Therfore to fight with it, Surface Baking Camera and Batch Baking Camera have "UV Border" option.

I showed how such things looks like in my BatchBakingCamera tutorial video:

Does it look similar to yours?

Try to use (temporarily) filled solid color texture image instead e.g. all white, to see if these patches will be gone.

 

[Sensei]

Obviously you should start from checking whether your object has 1 and 2 point polygons in Modeler Statistics window.

If "Render Lines" is enabled in "Render Globals" 1 and 2 point polygons are rendered..

 

[lertola2]

It might be because you have some geometry with polygons flipped the wrong way. So you are seeing through the polygons to the shadow they are casting. Try setting your surface to double sided and see if that fixes it.

 

[MartinSax]

Iertola2, that's seems to be closer to what my situation is.

I have attempted this as spoken & this has improved the situation i had, however i still have the issue remaining in places as described.

I tried unifying the polygons, which didnt seem to do the trick, is there anything else that could be done.

i have this horrible feeling that, this model....might be....sick and that's a awful feeling!, i cant think of any other way to go about this one to remove the double sides polygons.

 

[Sensei]

Did you perform cleanup the correct way?
i.e. first Merge Points, then Unify Polygons..

If you will execute Unify Polygons without Merge Points first, disconnected polygons sharing the same space won't merge together..

It is very easy to make such issues: e.g. by mistake use copy and paste. This will make duplicate of object having the same position and properties.

ps. You can simply attach object here in reply, and somebody will tell you where is problem..

 

[Sensei]

"Unify Polygons" merges polygons with the same vertexes (physically double sided polys, duplicates). There is yet another important tool in fixing objects: Unify Normals, which will try to flip polygon normal to point at the same direction. But it works only if you have no duplicated geometry sharing the same position and properties.

 

[lertola2]

Could you upload the object and scene so we can take a look? In your last image there is a lot of grainy darkness along the edges. Is that part of your texture? It seems to me if you could get rid of that the image would be fine.

 

[MartinSax]

Well hey Presto!,

that did the trick, Merge Points -> Auto

Then unify polys!, you sir are a legend!

thanks you for helping in this situation, i generally thought i had made a terminal error on this one!

i have attached another picture of the model with the proper look for people future reading this post!

thanks again everyone!

M

 

[Sensei]

After Merge Points, Unify Polys, Unify Normals, you should open Polygons Statistics window ('w' shortcut), and check if there are any 1-2 point polygons. Because Merge Points may make 1-2 point polygons e.g. you have quad polygon which has all four points in the same position e.g. 0,0,0 and you will use Merge Points, you end up with 1 point polygon. They are renderable if Render Globals > Render Lines is turned on. So, you should at least check if they were created, and eventually delete if they were created.

 

[erikals]

Nice model.