Problem Sharp edges

[Longjap]

Hi everybody,

I'm having a hard time making sharp edges. In Blender they look fine but when I convert them to Orbiter my cubes and cylinders look like turds.

I've read about making multiple vertices at the edges to create sharp ones in the SDK docs. This only sometimes seems to help and is a lot of work. I'm wondering how the seasoned mesh builders are creating sharp edges that look fine in orbiter.

 

[Hielor]

In Wings3D, you can designate an edge as being "hard" which will ensure that it's a sharp edge instead of smoothed. IIRC, the Orbiter msh exporter for Wings3d can respect "hard" edges and have the resulting converted msh show up correctly, although I might be totally making that up, I haven't touched it in years...

I'm not familiar with Blender, maybe it has a similar option?

 

[Hlynkacg]

I sounds like you haven't marked your edges as "Sharp". If you don't mark the edges of a mesh as sharp Blender will try to render your shape with the absolute minimum number vertices required. This can cause shading issues when you export it. See this tutorial, and look up "mark sharp" and the "edge" modifier in Blender's documentation.

ETA: I also suggest switching your shading mode from "flat" to "smoothed" to get a more accurate feel for what the exported mesh will look like.

 

[4throck]

Simple:

In Blender, select your objects (object mode) and choose Shading » Smooth.
On edit mode, select the face(s) you wish to be flat and duplicate (with no movement) or extrude (again with zero movement) them.

 

[Longjap]

I sounds like you haven't marked your edges as "Sharp". If you don't mark the edges of a mesh as sharp Blender will try to render your shape with the absolute minimum number vertices required. This can cause shading issues when you export it. See this tutorial, and look up "mark sharp" and the "edge" modifier in Blender's documentation.

ETA: I also suggest switching your shading mode from "flat" to "smoothed" to get a more accurate feel for what the exported mesh will look like.

Thanks. If I export it to orbiter mesh how will orbiter know if an edge is marked sharp? I've the orbiter import/export add-on in blender. Is there something added in the mesh file for orbiter to know?

I've noticed if I use >mark sharp alone doesn't help when I look in smooth mode. Only when I set Autosmooth in the mesh properties it creates what I want.

---------- Post added at 07:37 PM ---------- Previous post was at 07:32 PM ----------

Simple:

In Blender, select your objects (object mode) and choose Shading » Smooth.
On edit mode, select the face(s) you wish to be flat and duplicate (with no movement) or extrude (again with zero movement) them.

Will this not add to your total vertices count?

 

[Hlynkacg]

Thanks. If I export it to orbiter mesh how will orbiter know if an edge is marked sharp? I've the orbiter import/export add-on in blender. Is there something added in the mesh file for orbiter to know?

I've noticed if I use >mark sharp alone doesn't help when I look in smooth mode. Only when I set Autosmooth in the mesh properties it creates what I want.

Assuming that your're using Vlad's Import/Export pluggin, make sure that the "apply modifiers" option is checked in the bottom left corner of the screen when you go to export your mesh file. The pluggin should take care of the rest.

The main difference is in how the faces and normal are defined.

Will this not add to your total vertices count?

It will.

 

[Longjap]

Assuming that your're using Vlad's Import/Export pluggin, make sure that the "apply modifiers" option is checked in the bottom left corner of the screen when you go to export your mesh file. The pluggin should take care of the rest.

The main difference is in how the faces and normal are defined.



It will.

Yeah, I do make use of Vlad's add-on. Modifiers checked. I've marked everything I want sharp. Still it renders wrong in orbiter sadly. When I uncheck auto-smooth in blender the mesh also looks smoothed out in blender and not sharp. Not sure what causes it.

---------- Post added at 09:28 PM ---------- Previous post was at 09:19 PM ----------

Notice also the shading of the rest not correct. I usually correct that in mesh wizard by creating normals. But that's not as it should be I think.

 

[Hlynkacg]

Hmm...

This may be an issue with your specific blender setup, try adding an "edge split" modifier to the object in question and see what happens. You also shouldn't be marking the whole object sharp (unless that is your intention), as it eats up memory, just the edge loops you want sharpened on export.

 

[Longjap]

Hmm...

This may be an issue with your specific blender setup, try adding an "edge split" modifier to the object in question and see what happens. You also shouldn't be marking the whole object sharp (unless that is your intention), as it eats up memory, just the edge loops you want sharpened on export.

Edge split modifier is doing magic! It came to mind to actually watch the tutorial you linked. :lol:

Thanks for your help, this was my most annoying issue. No more turds.
The guy is also using a technique to lessen polycount of objects but still looks sharp. This was still abracadabra. I have to look into that.

 

[Hlynkacg]

Glad I could help, feel free to shoot me a message if you've got further questions.

 

[hutchison66]

Shading problems

Hi I have the same problem with AC3d most meshes are fine but every so often get shading that I don't want the rest of the meshes are ok but I merge a lot of meshes and that is where the problem arises was thinking of asking Donamy how he deals with this as he pretty good in AC3D
it probably is the edge detection as you've been talking about
thanks
David

 

[Donamy]

Try unwelding the corner vertices. Or better yet, change the crease angle in the objects manager tool to about 20.