3D Models and Terragen - Basics

Started by j meyer, July 03, 2015, 03:17:21 pm

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j meyer

Here are a few different versions of the cube so you can have a look and then
maybe decide for youself,if it suits your needs or as Ulco put it,if it's good or bad.
Most likely it will depend on your project(s) anway.

The illustrations show both rendered result in TG and a wireframe,so you know
what is what.
Smooth subdivided 1x or 2x means after having installed the stopping loops,
just to remind you.

#1
[attachimg=1]

#2
[attachimg=2]

#3
[attachimg=3]

#4
[attachimg=4]

#5
[attachimg=5]

As stated above it will most likely depend on your project and your pretensions
what is tolerable and what is not.

And again that's all for now.

Dune

This is a great thread, Jochen. Thanks very much. I am still relatively new to modeling, so it's an eye opener. It would probably go too far to explain how to create edge loops (I do know multishift) and (easily) delete unwanted subdivision in LW?

j meyer

Unfortunately I have no personal experience with LW and a quick look at
the LW7 manual didn't really help as LW seems to have a pretty different
modeling.I could not find any edge tools.Seems LW does the modeling
just by manipulating points and faces.(and curves etc)

I could only show exact steps for wings3d,if you think that'd be of help to you.

Maybe a long term LW user can help us out here.Please.

Kadri


Have a look at this video for example Ulco.
There are different ways and some plugins for edge loops. He mentioned some plugins too in the video.

https://www.youtube.com/watch?v=ipFEI3R_rDM

One way for getting rid of unwanted surfaces is selecting the surfaces and using the "Merge Polys" command in the "Detail" tab in modeler in polygon mode.



Dune

July 15, 2015, 02:00:00 am #49 Last Edit: July 15, 2015, 02:35:16 am by Dune
Thanks guys. I don't want to take over this thread, but thanks to you I discovered the edge bevel. And more after seeing the tut...

j meyer

Thanks Kadri. :)

No problem Ulco this thread is meant for stuff like that.




Oshyan

This is a really useful thread. But I think the post-question-response(s)-repeat forum discussion model is not a good way to present such information. It means the information is harder to find - it must be culled out from amongst other responses - and that incorrect or outdated information is harder to avoid/eliminate/update. A Wiki approach is ideal to solve this kind of need for potentially collaborative documentation/information and ongoing updates and improvements. So I would strongly suggest creating a Wiki page in the user-generated content area of the Planetside wiki to hold the "final" version of this info. For this, and especially in the future, I think it may be best to start the Wiki page, then start a forum thread to discuss it, but keep all informational and content posts in the Wiki, with only discussion, Q&A, etc. here in the forums. Note that there is also a discussion method in the wiki that could be used, but I imagine most people would prefer to do it here (this forum is a lot more full-featured and easier to use for discussion, for one thing).

Wiki is here: http://planetside.co.uk/wiki/
And is open and freely editable by any forum member. Just use your forum login credentials.

- Oshyan

bobbystahr

Quote from: Oshyan on July 15, 2015, 09:02:50 pm
This is a really useful thread. But I think the post-question-response(s)-repeat forum discussion model is not a good way to present such information. It means the information is harder to find - it must be culled out from amongst other responses - and that incorrect or outdated information is harder to avoid/eliminate/update. A Wiki approach is ideal to solve this kind of need for potentially collaborative documentation/information and ongoing updates and improvements. So I would strongly suggest creating a Wiki page in the user-generated content area of the Planetside wiki to hold the "final" version of this info. For this, and especially in the future, I think it may be best to start the Wiki page, then start a forum thread to discuss it, but keep all informational and content posts in the Wiki, with only discussion, Q&A, etc. here in the forums. Note that there is also a discussion method in the wiki that could be used, but I imagine most people would prefer to do it here (this forum is a lot more full-featured and easier to use for discussion, for one thing).

Wiki is here: http://planetside.co.uk/wiki/
And is open and freely editable by any forum member. Just use your forum login credentials.

- Oshyan



great idea
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

j meyer

I've put it here deliberately.From my point of view it should be a dialogue.
And I think we should collect some more related stuff and have people
asking their questions in relation to models in TG/modeling for TG first.
If only to find out what kind of info may be useful especially for the less
experienced for example.
In case someone wants to put it in the wiki later on we should be able to
find a solution.


Btw,how about that stuff about models in the Preview window (with and without
normals and normals flipped) posted in the support forum a while ago?
Should I post that into this thread,too?
What do you guys think?

Hetzen

July 16, 2015, 04:32:25 pm #54 Last Edit: July 16, 2015, 04:39:10 pm by Hetzen
A quick point on smoothing groups. It's not about smoothing the geometry, it's about smoothing how light works on the surface.

I've only ever modeled in Max and it's not really one of my disciplines. Most 3d software uses similar techniques just named slightly differently.

In Max, you have Smoothing groups, which allow you to apply smoothing across the geometry. The reason there are groups is so that if you want a curved surface to have a hard edge against another curved surface (like two sides of a clam shape where the lip comes to a hard edge), in Max you can apply the top half with smoothing group 1 and the lower half as smoothing group 2. This would then smooth the surface of everything within the group and not try and smooth around the desired hard edge.

A sphere should only have one smoothing group as there are no edges to differentiate.

What smoothing groups don't solve is how the outside edge of the object curves. This will always be faceted by the number of vertices you have in that object's plane of curvature.

As an example, a low poly sphere with 1 smoothing group will look smooth in the centre but hard edged at the sides as there is not enough vertices to define the curve around the objects edge.

Paq's post with the TV type object shows what happens when the object has only one smoothing group. The light interacts weirdly, because it's trying to smooth all of the surfaces together, when in fact there are various combinations of right angles to consider too.

Jochen has shown what you need to do to get a curved edge very clearly, you have to bevel it a few times and apply one smoothing group to the whole cube. This is really important with displacement in any program.

Back to Paq's TV, to get a correct effect he will need to bevel where he wants rounded corners and change the smoothing group number of the polygons where he wants them to have their own unique smoothing. So for example, the large beveled cube would have smoothing group 1 applied, the sides of the first extrusion (4 of them) would each have unique smoothing group numbers so that the right angle is maintained when shaded. The next level of extrusion would have another 4 if he wants to maintain the hard edge and so on.

Most programs have an auto smooth function within the polygon/mesh properties which does most of the work for you. You just set the threshold angle and let it do it's business. But you more often than not need to get into the mesh and add you own smoothing groups to certain surfaces that you want to distinguish between that may not fall within the threshold you've set.

Oshyan

Having a dialog (like this one) does not have to be "instead of" a wiki page, it can (and should be) *in addition to* a wiki page. This thread is potentially very useful and will get lost fairly quickly once people stop discussing it. Yes, we could Sticky it, but then we have a potentially long (already somewhat long) discussion thread that people have to read through to get what would probably be 1 or 2 pages of real, useful information, and they have to sift through questions, experiments, and potentially non-ideal solutions to get the best info. That's the value of having a wiki page: you can present distilled, "best practice" information and it never gets lost.

- Oshyan

TheBadger

Since there are other directions basic modeling can take you, such as sculpting, I wanted to point out that in most cases you would not want to subdivide when taking your object to sculpt.

With the example of the cube(s) from this thread, you would make the shape and scale, but not subdivide until you got to your sculpting soft. The reason is that you want very even and uniform polygons. Wen you start removing edges and verts as in the examples on this thread, you will alter the normal effect of subdividing further. The result will be uneven distribution of polygons over the shapes like a cube.

Now when bringing your sculpt back to the original model to bake, you more than likely will want to subdivide, this will give the maps better results on your base model. But it is a case by case thing. Trial and error is a necessary part of it because every model is going to be different. The point is that the shapes/forms to take from your modeler to sculpt on be clean.

the idea of creating polygons by subdividing (smoothing) and then removing unneeded polygons (in Maya- the "remove edge and vert" command) Is a proven modeling workflow for sure. That is how I learned. With "digitalTutors, for example, this method is used in maya and pretty much all the other software that allow for it (which I think is basically all modelers).

I realize that going into sculpting takes us into more complex modeling (not exactly the "basics"). But I learned this lesson the hard way, and only want to point out that as a someone begins a modeling project, you want to be sure of how you plan to start and finish. There is a definite process and order of doing things in 3D modeling. And I know from pain, that you cannot always get good results in a sculpt from a base model that you have already done too much work on.



It has been eaten.

paq

July 16, 2015, 09:20:21 pm #57 Last Edit: July 16, 2015, 09:33:12 pm by paq
Hello,

Quote from: Hetzen on July 16, 2015, 04:32:25 pm

Back to Paq's TV, to get a correct effect he will need to bevel where he wants rounded corners and change the smoothing group number of the polygons where he wants them to have their own unique smoothing. So for example, the large beveled cube would have smoothing group 1 applied, the sides of the first extrusion (4 of them) would each have unique smoothing group numbers so that the right angle is maintained when shaded. The next level of extrusion would have another 4 if he wants to maintain the hard edge and so on.



On this example, if you are speaking in 3dsmax term, there is only one single group for the whole object. There is no need to break the normals, the extra edges are there to keep the shading 'right' or acceptable.



[attachimg=1]

Technically it's not really a bevel either, but more an edge shift, in both direction, for every edges you want to keep 'sharp' ...
in the same way you would prepare the mesh for a Catmull Clark surface subdivision.

In many package, bevel = rounded edge, fillet, or even chamfer. This commands can quickly add lots of complexity into the model,
and depending of the settings, it might even erase the initial edge position.

By shifting edges, or sliding them (again, it depends of the DCC software used), you keep the initial edge in place.
It makes further editing much more simple.

(That having said, you can do this modeling task on multiple edges at once in Modo, using the Bevel command  ::) , with 'sharp corner' + 'square edge shape' option activated)
Gameloft

Kadri

July 17, 2015, 12:13:36 am #58 Last Edit: July 17, 2015, 12:17:08 am by Kadri

Quote from: Hetzen on July 16, 2015, 04:32:25 pm
A quick point on smoothing groups. It's not about smoothing the geometry, it's about smoothing how light works on the surface.
...


Yes it is true for other programs.
But when you use displacement with the micropoly render in Terragen (ray trace OFF) it handles the geometry different.
So in Terragen it actually is kinda smoothing (holding the edges together) the geometry.

Matt said this:
"If the object doesn't have normals, Terragen defaults to using the face normals. These are usually discontinuous from face to face. If two neighbouring faces are displaced along a different normal then the object splits apart at the shared edge (Terragen doesn't fill in the gaps).

If the object has normals (vertex normals) and the normals are the same for each shared vertex (they are "smooth"), the normals at the face edges will be the same for all neighbouring faces, so displacement doesn't cause them the split separate.
"

From here:
http://www.planetside.co.uk/forums/index.php/topic,19431.msg190793.html#msg190793

With smooth normals practically it ends like that a very basic cube with 6 faces looks like it is heavily subdivided like in another program.

TheBadger

Because I am fixing some issues, Ill post this here as it is related to basics.

Non-planar Faces in TG.

In maya where I am modeling currently, Non-planar Faces are not a problem. Mostly you cannot even see it, but when you smooth normals, they can become very ugly.
The following is a description of Non-planar Faces:
     
QuoteNon-planar faces are polygons with at least four vertices that do not lie on the same plane. In other words the vertices of a Non-planar face no longer form a flat surface in 3d space. Non-planar faces are not necessarily bad; in fact Maya doesn't care at all. Objects with non-planar faces can be smoothed, rendered and all polygonal tools should still work fine. When modeling for a game engine Non-planar faces may cause problems, but luckily they can be fixed without any problems. Cleanup will find and highlight all non-planar faces and if told to cleanup it will triangulate all non-planar faces. In this case triangulation is the easiest method to fix non-planar faces since three sided polygons (also known as trigons) always form a plane in 3d space. If you are keen about keeping your model in four sided polygons (also known as quads) you will have to clean up the geometry manually. The best way to go about it is to use the orthographic views (front, side, top, etc.)

     
What I wanted to point out, is that non-planar faces will show as problematic in TG as well if normals have been averaged/smoothed. It appears like the renderer does not know what to do with the light, and makes those faces much darker or much brighter than the surrounding faces. The only fix is to go into the modeler and delete those faces, and replace them with planar faces (in maya--> select one edge and double click and delete---> mesh--->"fill hole")

At this moment I am not sure what happens to the normals when you delete a face and replace it.

Anyway, A lesson I learned, Model very very carefully even if you don't think you need to. There is always something waiting to kick you in the balls.
It has been eaten.