PDA

View Full Version : Annoying Dots



treddie
11-23-2011, 08:04 PM
I have a model I am working out textures on and came upon this problem. Instead of picking up a continuous bright highlight along slightly rounded edges, I am getting equally spaced dots instead (please see attached image). I have tried everything to get rid of the dots with no success. Does anyone have any ideas as to what is going on?

Many thanks!

Dexter2999
11-23-2011, 08:08 PM
Is this one of those dithering issues?

ShadowMystic
11-23-2011, 08:55 PM
Are you using radiosity? If you look, you have dots all along your edges where specular would hit. would you mind showing the scene or the model?

treddie
11-23-2011, 11:23 PM
No radiosity running...turned it off for my tests due to the speed limitations.
Thought it might be dithering, but I adjusted every appropriate parameter I could with zero effect. Also, there SHOULD be a bright specular highlight along those edges where the dots appear...they're just coming out as dots instead of a continuous highlight.

Here is a zip containing the scene. I deleted a bunch of the objects in the scene to simplify it, so the remaining objects are pretty small in the frame. But if you just run it from the containing folder and leave the settings unchanged, you will pretty much see what I see in those areas in the frame.

steve0077
11-24-2011, 12:02 AM
Way to many vertices and polys in your models. I'm pretty sure that's having effect on your texturing.

Mr Rid
11-24-2011, 12:03 AM
Basically, you dont have AA. Try adaptive sampling at .03 to .02. And oversample .5

I dont use gaussian since it is just blurring the image, which is better to post adjust in PShop or comp.

Also, the shadow map size is way overkill and needlessly taking more time. Increasing map size will proportionately decrease fuzziness- they counteract. You may cut both values by 1/4 to speed render yet get the same shadows. Although keep in mind that shadow maps are inherently inaccurate and will not cast proper shadows with fine or distant geometry.

Btw, there are also a lot of points in the model that are not attached any polys that could be removed.

treddie
11-24-2011, 12:58 AM
That was it! Thank you for your help. It has been about 12 years since I was heavy into LW so it is like starting all over again in many ways.

As for the extra points, I had thought that when I exported out from Creo, and processed through PolyTrans that I had taken care of extra points and coincident surfaces. Thanks for pointing that out, because now I need top go back into my work flow and see where I'm missing an important step.

Steve0077 > I am a bit eccentric in my high poly counts only because I hate building more than one model for my type of work and always want a no-fuss, easy way to just zoom in on my models to however close I want to get without having to worry about tesselation, especially along edges. I have the horse-power to get away with it and am getting ready to build a small render farm. But also, I am planning on selling some models online and that raises the issue of my models fitting into other people's pipelines. So the poly counts will definitely matter then. I'll need to reexamine how to keep high poly counts where it matters (like the leading edge of a wing) and a drastic drop off for other areas (like the top and bottom of a wing). Things like spheres don't seem to have an easy solution...if you zoom in on a relatively low poly sphere, you are definitely going to see a bunch of flat edges along the perimeter.

biliousfrog
11-24-2011, 01:06 AM
Steve0077 > I am a bit eccentric in my high poly counts only because I hate building more than one model for my type of work and always want a no-fuss, easy way to just zoom in on my models to however close I want to get without having to worry about tesselation, especially along edges. I have the horse-power to get away with it and am getting ready to build a small render farm. But also, I am planning on selling some models online and that raises the issue of my models fitting into other people's pipelines. So the poly counts will definitely matter then. I'll need to reexamine how to keep high poly counts where it matters (like the leading edge of a wing) and a drastic drop off for other areas (like the top and bottom of a wing). Things like spheres don't seem to have an easy solution...if you zoom in on a relatively low poly sphere, you are definitely going to see a bunch of flat edges along the perimeter.

Sounds like you should be using subdivision surfaces rather than creating everything at the highest detail level possible everytime...especially if you're looking to sell models online. Let the Sub-d's (and the end user) determine the detail level and keep the poly count and file size to an acceptable level.

treddie
11-24-2011, 01:31 AM
I have to confess ignorance here, but if you start with a triangular mesh like from an .obj file, can you convert to a Subid surface? In other words, how can a converter understand how to subdivide a "dumb" surface that contains no information about its intended shape? If I have a low-poly sphere and want to subdivide it to give it a higher poly count in Lightwave, as I recall, I just end up with the same polyhedron with more faces for each original face.

stiff paper
11-24-2011, 03:34 AM
if you start with a triangular mesh like from an .obj file, can you convert to a Subid surface?

You'd want to convert it to quads, at least as much as you can manage to. There were plugins to help with this, "MergeTrigonsX" was one, but I don't know where that's disappeared to (and it never really helped when I tested it anyway.)

With most models it's not really all that painful to do it by hand in the perspective view, hand hovering over Shift-Z. Or maybe I just feel that way because I've had to do it so many times.

treddie
11-24-2011, 03:48 AM
I'll give it a try tomorrow. Er...today...it's 3:00am!

treddie
11-26-2011, 10:01 PM
There were plugins to help with this, "MergeTrigonsX" was one, but I don't know where that's disappeared to (and it never really helped when I tested it anyway.)

I tried it too, but LW 10.1 won't accept it as a valid plugin. I actually found a standalone progy called AccuTrans 3D ($20) that handled the tris to quads conversion. Seems to work with no apparent problems (but how reliable is a comment like THAT when I've only tested it about 3 times, eh!?). Only problem is, it is yet another program in the flow.

But in the attached image, you can see LW in "normal mode" and in the next image, in SubD mode. The SubD view is whacked out in that LW doesn't seem to be able to smooth the form in an acceptable way, based on the underlying geometry, if you look at it closely.

So the conclusion (right or wrong) that I came away with was that going from the "raw" hires model on the left and simply letting the user reduce polys to get any under-res from there (on the far right) was my only option, rather than using sub-division.

I have also severely dropped my poly counts down for any models I plan to sell, by finding the right export settings to stop triangulating perfectly flat surfaces unless it has no other choice (I was able to drop my poly counts of complex surfaces roughly 20 to 30 times without much reduction in quality for the most part).

Keep in mind, also that since I do not build my models natively in LW (I use a solid modeler), that my only option is to go from solid model via its exporter to .obj surfaces. The exporter (or any others I have seen) do not take into account the direction of extrusions, revolved solids and such, so that the resulting .obj file is composed of pretty much random triangulations that result in those nasty "sliver" triangles that are almost impossible to get rid of. I don't see any way to get the "orderly" meshes you see in most TurboSquid models. Oh well, I guess.

dwburman
11-26-2011, 11:08 PM
You would want to do the poly redux before using subD mode. Basically, the lower-res geometry acts as a cage that the subD mode uses to make the geometry. If the mesh is already sufficiently high res, then you're just adding a ton more geometry for no good reason.

Of course, since you're modeling in something else and importing it into LW, it may not be worth the effort to down-res the models for your own use if they are working fine for you right now.

treddie
11-26-2011, 11:22 PM
Well, for my OWN purposes, they work great. But for selling purposes, I may have to do a bit more work to get them so they fit well with other people's work flows. Going in and optimizing my poly counts is one example. But the problem I see right now is that since converting from solid model to surface mesh results in a very random, "sloppy" set of triangles, they look like they do not lend themselves to orderly, predictable cages. Solid to mesh conversion with an orderly cage approach looks to me like that is really a capability that has never been explored before by any programmers. As a programmer myself, I don't see that that would be an impossibility for someone familiar with the math.

Come to think of it, I'm going to ask the people at PTC and Okino, what's up with that.