Meshing Question removing unwanted creases/ridges

[malisle]

I need some help regarding mesh smoothing in gmax/3DSmax. There is a cone that will become a command module someday and I wanted to drill some RCS holes in the mesh. ProCutter and ProBoolean do a great job, but when i apply mesh smoothing afterwards i get weird creases/ridges on what should be a smooth surface. 3DS max help states that when this happens number of faces should be increased. Unfortunately, many faces dissapear after the first cut has been made (pic 2). If no mesh smoothing is applied, there are no ridges but the cylinder is blocky. Here are some pics.

Geometry before cutting:

Geometry after the first cut has been made:

After cutting (notice ugly creases):

In Orbiter (notice ugly creases):


Any advice?

 

[Donamy]

Did you weld all the vertices ? You could also use tranparent covers, on the thrusters that when placed before the hull in the group list, will make the holes, without cutting them in the mesh.

 

[Capt_hensley]

Don't forget that increasing the number of faces will create more polys, which affect your frame rate in orbiter. Dons idea with transparencies sounds like the better solution.

I use 3DS Max 2013 extensively. I've a great deal of head banging with it, learning different techniques. Getting smoother appearances for me comes from working with 90-150 faces depending on the object, and level of detail I want. High Res textures also have disadvantage with frame rate. Most of my advanced textures are 2048x2048, 600dpi.

As you can imagine getting these meshes loaded into orbiter poses quite a challenge. One I haven't been able to solve without compromising smoothness or texture clarity at high zoom levels.

Good Luck.

 

[malisle]

Did you weld all the vertices ? You could also use tranparent covers, on the thrusters that when placed before the hull in the group list, will make the holes, without cutting them in the mesh.

Yes, the vertices are welded. Transparent covers are a great idea, but since they are transparent, how would I get a backside and depth of the thruster hole? Also, wouldn't I be able to see right through the mesh on the other side since the mesh is only visible when viewing from the outside?

---------- Post added at 07:48 ---------- Previous post was at 07:42 ----------

Don't forget that increasing the number of faces will create more polys, which affect your frame rate in orbiter. Dons idea with transparencies sounds like the better solution.

I use 3DS Max 2013 extensively. I've a great deal of head banging with it, learning different techniques. Getting smoother appearances for me comes from working with 90-150 faces depending on the object, and level of detail I want. High Res textures also have disadvantage with frame rate. Most of my advanced textures are 2048x2048, 600dpi.

As you can imagine getting these meshes loaded into orbiter poses quite a challenge. One I haven't been able to solve without compromising smoothness or texture clarity at high zoom levels.

Good Luck.

Well, this model does have a high poly count for almost nothing to show (~2000) but the FPS in Orbiter is around 1200 at the moment.

 

[jedidia]

Well, this model does have a high poly count for almost nothing to show (~2000) but the FPS in Orbiter is around 1200 at the moment.

One mesh with that polycount won't affect anything much. Several of them, however, will start to show some impact, depending on your GPU. If you have a kick-ass GPU you can put a mesh with 100,000 faces in there and it won't even notice. If someone with an older GPU loads the same mesh, he'll get a slideshow.

Anyways, about the issue at hand: The first is, those holes are pretty small... I can't make out the scale of the thing, of course, but if it's somewhere along the lines of a typical ISS module it might be worth thinking about adding such small details in the texture.

Second, did you reassign the smoothing groups? I assume you created the cone out of a cylinder, which comes with smoothing already applied at creation, but cutting it will mess up that smoothing group. You have to apply a smooth modifier. Either autosmooth, where you can define a threshold angle, or manually assign the smoothing groups. If the vertices are welded correctly, this should get rid of the problem.

 

[Hielor]

Rather than actually cutting the geometry, you'll want to make the inset RCS holes a separate object, so the "surface" of the command pod remains uninterrupted. Then make the corresponding polygon on the surface of the command pod either transparent or excluded from export to Orbiter. The resulting effect is that the surface of the command pod will maintain its smooth appearance, while you have a flush inset piece as well.

I don't know how to do this in 3ds max, but I have a tutorial for the procedure in Wings3D here:

 

[liber]

Main problem with circle is how some program link circle to end of face.
Try this each hole put into square something like this.
This can reduce problem with model.

 

[malisle]

One mesh with that polycount won't affect anything much. Several of them, however, will start to show some impact, depending on your GPU. If you have a kick-ass GPU you can put a mesh with 100,000 faces in there and it won't even notice. If someone with an older GPU loads the same mesh, he'll get a slideshow.

Anyways, about the issue at hand: The first is, those holes are pretty small... I can't make out the scale of the thing, of course, but if it's somewhere along the lines of a typical ISS module it might be worth thinking about adding such small details in the texture.

Second, did you reassign the smoothing groups? I assume you created the cone out of a cylinder, which comes with smoothing already applied at creation, but cutting it will mess up that smoothing group. You have to apply a smooth modifier. Either autosmooth, where you can define a threshold angle, or manually assign the smoothing groups. If the vertices are welded correctly, this should get rid of the problem.

Base diameter is arround 7m, height 5.5m. RCS holes are small, but only by chance since this is just a model for me to learn on.

Yes, I did. Starting object is a cone (no need to deform him, just define top and bottom radius and height) made without any mesh smoothing, with certain number of sides and height segments. After all the cutting has been done smoothing is applied. I tried working with both smoothing groups (minding the common groups) and autosmooth but the mesh was still wrinkled.

Rather than actually cutting the geometry, you'll want to make the inset RCS holes a separate object, so the "surface" of the command pod remains uninterrupted. Then make the corresponding polygon on the surface of the command pod either transparent or excluded from export to Orbiter. The resulting effect is that the surface of the command pod will maintain its smooth appearance, while you have a flush inset piece as well.

Imprinting the polygon on the surface creates the same wrinkles as boolean subtraction, so I have to work more to get the same problem


Here is the .max file, if anyone feels like trying...
View attachment test01.zip

 

[Hielor]

Imprinting the polygon on the surface creates the same wrinkles as boolean subtraction, so I have to work more to get the same problem

What other ways do you have in MAX of subdividing the surface? In Wings3D you can subdivide while maintaining the curvature. Rather than "imprinting" the polygon on the surface, in Wings3D I would build the polygon on the surface through subdivision, then "lift" that off the surface to create the new object.

 

[malisle]

What other ways do you have in MAX of subdividing the surface? In Wings3D you can subdivide while maintaining the curvature. Rather than "imprinting" the polygon on the surface, in Wings3D I would build the polygon on the surface through subdivision, then "lift" that off the surface to create the new object.

You mean extruding the polygon inside to form a hole (as a new object)?

 

[Donamy]

Yes, the vertices are welded. Transparent covers are a great idea, but since they are transparent, how would I get a backside and depth of the thruster hole? Also, wouldn't I be able to see right through the mesh on the other side since the mesh is only visible when viewing from the outside?

You have to make the thrusters themselves as a seperate group, placed before the transparent covers in the group list, so they are seen through the covers and hull, but not through to the other side.

 

[Hielor]

You mean extruding the polygon inside to form a hole (as a new object)?

Yes.

 

[Donamy]

The first pic is of the mesh, without the transparent covers. Notice that you can't see through the hull. The second shows the mesh with the transparent covers.

 

[malisle]

All right, thanks for the help. I got a lot of information and ideas, I will make it work :thumbup:

 

[francisdrake]

Hi, I did a quick modelling in Gmax, just a cone intersected by a cylinder.
The first picture shows the two shapes before merging, the second one after merging. There is a slight distortion of the cone shape, which gets less when increasing the number of sides of the cone (here: 48)
But as you see the distortion is quite slight.
I use the function: Create compound objects, Boolean, Subtract.

One remark on low-poly modelling: While increasing the number of sides makes a cone look 'rounder', the number of vertical divisions (layers) does not improve its shape. I always try to create the model with the least amount of polys required. So the framerate is easy, even with other vessels in view.

 

[Capt_hensley]

Hi, I did a quick modelling in Gmax, just a cone intersected by a cylinder.
The first picture shows the two shapes before merging, the second one after merging. There is a slight distortion of the cone shape, which gets less when increasing the number of sides of the cone (here: 48)
But as you see the distortion is quite slight.
I use the function: Create compound objects, Boolean, Subtract.
One remark on low-poly modelling: While increasing the number of sides makes a cone look 'rounder', the number of vertical divisions (layers) does not improve its shape. I always try to create the model with the least amount of polys required. So the framerate is easy, even with other vessels in view.

Compromise, Polys vs appearances, if it's just the capsule, a High-res mesh can be invoked after launch. That way the launch does not suffer from frame rate drag. Once in orbit, the capsule by itself will have a lower poly count than the entire LV with Capsule... and so on... At least that how my GWS modules are working so far.

 

[Hielor]

Hi, I did a quick modelling in Gmax, just a cone intersected by a cylinder.
The first picture shows the two shapes before merging, the second one after merging. There is a slight distortion of the cone shape, which gets less when increasing the number of sides of the cone (here: 48)
But as you see the distortion is quite slight.
I use the function: Create compound objects, Boolean, Subtract.

<snip>


<snip>

One remark on low-poly modelling: While increasing the number of sides makes a cone look 'rounder', the number of vertical divisions (layers) does not improve its shape. I always try to create the model with the least amount of polys required. So the framerate is easy, even with other vessels in view.

Your "after" model has not been triangulated. Since Orbiter only supports triangular faces, the model will need to be triangulated during export. This will add faces, and more importantly, result in additional creasing/distortion in the curve of the cone.

 

[francisdrake]

Your "after" model has not been triangulated.

Fair comment.
I converted it to a mesh, and indeed the edges showed up. (first pic)

When zooming in very closely I saw they are caused by vertices very close together, leading to edges close together, but in different planes.

I selected the vertices and welded them. This needs some playing around with the treshhold value, but in the end these extra vertices were combined and the mesh looked acceptable. (second pic)