3d introductory part 3 updated

8/4/2019 3D Introductory Part 3 Updated

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3D Introductory Part 3/14

A series of lectures created for students at candidate level at the IT-University of Copenhagen by Rickard Stampe Sderstrm 2011. [email protected]. All material in this lecture is copyrighted to the autors and creators of the pictures and films. And the lecture is copyrighted to Rickard Stampe Sderstrm. You may freely use it as a presentation but not printing it in a digital or analog form.


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Modelling


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Edge The line

between twoedges

Vertex One position in the 3Dcoordinate system

Face Is defined by three ormore vertexes. Can bemoved, rotates, andscaled

Normal Indicate thedirection of the faceUV coordinates2D coordinates on the model,

used for texturing

A POLYGON MODEL


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Polygon modeling

(greek polygon = many edges)

- The most commonly used modeling method.

- Model the "shell" of a form.

- A model technique that resembles how you make a "roof" by laying more and more tiles.


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Extrude surfaces

Split polygon Tool

Extrude surface with keep faces

together

Primitive Poly Cube

Extrude surface

Basic PolygonTools

Extrude edge

Extrude surface with out keep

faces together


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Make a low resmodel first thenmake it highres.

Model with a halfproxy model

Basic polygon modeling


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Smoothing polygons for higher res.

Smooth preview without extra edge loops for sharper curvature

Smooth preview with extra edge loops for sharper curvature

Model by Emil Nygaard


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Top illustration: Romainbehar / Wikipedia Commons Bottom illustration: Mns Larsson

SubD MODELS


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NURBS Modelling

- NURBS surfaces (NON RATIONAL B-SPLINE)

- Used in CAD / CAM mostly.

- Modelling using with Curves and Surfaces

- Not a common modelling technique anymore

- NURBS can be converted to Polygons.


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U-value = 1

U-value = 0

The point define the form of the curve

The endpoint of a span(curves are made fromspans)

A square indicates the start

of the curve

Connecting the CV pointswith a straight line forediting them in a effectiveway.

A point on the curvedefining a curve value in U.

Connecting the CV pointswith a straight line forediting them in a effectiveway.

A surface definedby four isoparms.

The point define the form

of the curve

A curve defining the formof the surface (defined by

CV points)

U-value = 1

U-value = 0

V-value = 1

A NURBS Surface

A NURBS Curve


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4 WAYS OF CREATING A GOLF PIN!


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4 modelling techniques for a golf pin

- 1) Modeling from aprimitive

- Create a PrimitiveNURBS or POLYGON andshape it to the form of agolf pin.


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- 2) Modeling from NURBSCURVES

- Create a profilecurve of

the golf pin and "Revolve"it to create a surface

- Try altering the curveafterwards and see how"history" in Maya works

- Delete History.

- Now alter it.


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- 3) Modeling withPolygons

- Using Extrude andtransforms you form thegolfpin

- Try smoothing it!


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- 4) Modeling with Booleanoperations

- Using 3 PolygonsSpheres and edge loops.


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Modelling a cart

Model by Dariush Derakhshani from the book Introducing Maya 2011


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Modeling a cart

- Cut in Photoshop and place reference material in scene. - Start with a primitive Poly box and shape it and insert edgeloops.- Extrude it... and...


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Modeling a cart

- Make Bevel on the edges.


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Modeling a cart


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Modeling a cart

- Booleans - difference - making a hole in the mesh for handel.


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- Split polygon and use Wedge Polygon tool

Modeling a cart


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Modeling a cart- Build bottom from a primitive cube.

- Add edge loops on the side

- Extrude the front and back panel - Bevel them with width 1 and 12 segement


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Modeling a cart- Model bumper with cylinder and cut it with Cut

Faces Tool


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- Smooth panels and mirror the panels

Modeling a cart

d l


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- Revolve tire from NURBS curve by making a profile curve forthe tire and hubcap.

Modeling a cart

M d li


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Modeling a cart

M d li


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- Model the wood panels with the same technique: place cubes,shape them after reference pictures and bevel the edges.

Modeling a cart

M d li


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- Adding the details (screws etc), by making holes withbooleans and modelling the screws from primitive cylinders.

Modeling a cart


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FINISHED... or what?


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What about topology?

Topology


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Topology

- Is the way you order the polygons in the mesh depending on allot ofthings?

- Is it a Organic or Static object? (if the car is just cruising it might be astatic object, but the frame it crashes in to a wall and deform itbecomes a organic)

- Are you doing models for a game enginge?

- What rendering are you using?

- What is the diffrence and how does it effect topology whenyou build the model?

Topology


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Topology

How many edges do thissurfaces have?

Topology


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Topology

How many edges do thissurfaces have?

Topology


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Topology

A render in Maya calculates the modelokey. The holes are probablymodeling errors, but you can see thebevel in the surface structure.

A render in Mentalray render isalso okay, some minor issues.

hmmm... so what is the problem?

Topology


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TopologyDifferent type of polygons

3 Categories: 1. Triangels (Tri's)

2. Quadrates (Quads)

3. N-sides (all surfaces more then 4edges, often just referd to n-gones)

Topology


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Topology- Most deformation brakes n-sides (five edges or more) andtriangels so you can see the individual polygons of the

surface.

- N-sides can be a problem in other externely renderprograms.

- Most game engines need to triangulate the model(converting the mesh to only triangles). It can also be aproblem with a mesh like this.

- Textures can stretch and look weird.

- You can build a lowpoly model with quads and smooth it laterin the render using SubD-surfaces. (all smoothing tendsto needs quadrates)

- Bad topology mean render errors can show in the image thatdoesn't show on the display preview in the program (likeduplicated surfaces). And in rare situations the model does notrender at all, or crash the whole render.

- But allot of the topology problems doesn't matter... but youneed to test and understand your needs for the texturing,

animation & rendering when evaluating your modeling.

Topology


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TopologyMajor topology issues:

- The best topology is a mesh, with evenly spaces edge loops, ina mesh of all quads (quadrates). Containing no n-gones ortriangles. (it can be converted to triangles for some gameengines and works in all renders and texture situations)

- Surfaces flow after the "natural direction", like muscles etc.

- No Lamina Faces, ex: duplicated surfaces, edges or vertexeson top of each other.

- All normals on the surfaces pointing out from the surface.

- Non manifuld geometry. Basically forms that can not exist inreality. Faces just sharing a vertex, three faces sharing an edge,or opposite surface normals

- No holes in faces.

- No "unmerged" vertexes in mesh that is ontop of eachother.

Illustrations from Count Zero, more pictures look here: http://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and- fix-it

Extra edge loops for bending deformations

Topology
http://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-it


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TopologyMinor topology issues:

- Non-Planer Surfaces

- Concave Surfaces

- UV- coordinate errors

- And on occasion you can placea triangle on the mesh were it is

not deforming, like backside ofthe skull etc.

- For a static model usually oneor two n-sides are fine.

Illustrations for Count Zero, more info here: http://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and- fix-it

Can you find the n-side?

Topology
http://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-it


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TopologyHow can you fix topology issues:

- Use the Cleanup mesh function in Maya and othersoftware.

- Fixes faces/vertexes ontop of each other - Fixes some holes - Can convert the geometry to triangles. - Or just highlight problematic areas.

- Manually make four sides from n-gones and triangles.

- Change the direction of the surface by "split polygon tool"or "spin edge"

Illustrations for Count Zero, more info here: http://www.3dbuzz.com/vbforum/showthread.php?157 746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix- it

Manually fixing flow: http://lesterbanks.com/2011/03/polygon-topology- techniques/

Topology
http://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://lesterbanks.com/2011/03/polygon-topology-techniques/http://lesterbanks.com/2011/03/polygon-topology-techniques/http://lesterbanks.com/2011/03/polygon-topology-techniques/http://lesterbanks.com/2011/03/polygon-topology-techniques/http://lesterbanks.com/2011/03/polygon-topology-techniques/http://lesterbanks.com/2011/03/polygon-topology-techniques/http://lesterbanks.com/2011/03/polygon-topology-techniques/http://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-ithttp://www.3dbuzz.com/vbforum/showthread.php?157746-Tutorial-Bad-Geometry-%96-How-to-find-and-fix-it


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Topology

But the best way of "fixing" topology issues is bymodeling it in quads in the first place!

Topology


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Topology

- Starting from a plane with four faces.

1 2

3 4

Topology


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Topology

- Bevel the lowpoly surface with two segment option tokeep the quads and a roundnes of 0.2

Topology


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Topology- Bevel the lowpoly surface with two segment option to keep the quads and a roundness of0.2

Bevel (or manually place edge loops) on the edges on the frontand backside. Then press 3 to see a smooth preview

Topology


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- Using more edge loops for sharper edges in the mesh.

- ex: 2 edge loops close together for a semi-sharp edge

- ex: 3 edge loop close together for a harp edge

Topology

Topology


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p gy

Making a hole with a Boolean using a 8division cylinder and connecting it with

the mesh.

Merging the edges with the hole forcontiues edge loop on mesh and building

a ring around the hole with "split polygontool" and "merge tool"

Press "3" to see the preview of thesmooth surface. The hole is to "round"and "soft"

Add edge loop with "Add edge loop tool" Now the surface look nice in smoothpreview mode.


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Topology


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p gy

Translating (moving) the vertex point tothe the nearest vertex point using snapto point (v) and merging them, willremove the extra face. (Always avoiddeleting edges, the whole face candisappear if you do.)

Topology


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p gy

A new clean up selects this N-gone.Hmm... that doesn't make sense?

Topology


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p gy

Moving around the vertex points for theindicated N-gone reveals that there is anextra vertex right on top another...Merging them into one vertex will solvethe problem.

Topology


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The next cleanup is clean! The surface is cleaned up. Delete history and freeze transforms.

Topology


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Using a primitive plane with 4 divisions I extrude the edge of it down.This whil create the edge loops I want over the surface.

I place a cylinder with 16 sections (8 is minumum I think for getting a goodrounden form). Using the cylinders vertex positions I extrude the edge to these

positions.

Topology


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Deleting these faces so I get aclean edge to extrude from later

on.

Translating the vertexes to match the reference material

and my surface.

Adding more edge loops to thesurface.

Topology


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Beveling the cornersExtrude the width of the surface

from the edges.

Clean up the surface and look insmooth preview mode.

Topology


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Duplicate and align with reference and adjust the reference planes.

Topology


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Rebuilding the bottom to quads using more edgeloops on the sides and extruding the edges. You neversee in the model that it is shallow because of the redpanels "cover" it up.

The old bottom containt n-gones

Topology


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Rebuilding the bumper by inserting edge loops on therounded corners (making it enabled to be smoothed)and removing faces you will never see that mightintersect other geometry and create longer rendertimes therefore.

New tire using the NURBS revolvetechnique (the same as the old one).But with "CV" option on for making it aslowres as possible. It creates goodtopology and can be smoothed later.

Topology


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The new "quad" wagon, clean up, deleted history and freezed transforms.

Topology


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The starting point for the wood panels on the sides of the cart.


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Topology


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Placing two cylinders for using in a Boolean operation?But the Bolean "difference" I used before is nowproducing something different, why?

Before the Boolean After the Boolean

Topology


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Looking at the normals of the surface gives me theanswer - they are pointing inward!

Reversing them in the menu "Normals" make the flipso the surface is now pointing outwards.

Now it is working! Adding extra edge loops around the hole and addingbevel or extra edge loops on the edges of thewodden panel, and it is finished.

Topology


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I'm repeating the same technique for the bottom wooden panel.

Topology


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For the railing, the wooden panel is attached to, it is the sametechnique again. Starting modeling from a plane and extruding, firstthe bevel and then scaling it up adding extra edge loops on the edgesfor sharper curvature.

Topology


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A "cleanup" find n-gones!

Topology


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Fixing the n-gones with anextra circle of edge loops thatcreates "poles". Poles arefine, but should not be placedwhere heavy deformationsare.

Topology


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Arrange the model also in outliner, save and "optimize scene" and saveagain.


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Dariush Derakhshani's model with N-sides on the left and R.S.Sderstrm model with quads on the right.


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Modelling the Fiat


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Refrence material for modelling


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- Cut into reference imagesinto separate images

- Import them in Maya by"importing Image planes" inpanels

- Adjust size and placementin Channel Box

- Make a 3D-sketch with exNURBS curves.

First steps of modelling the car


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- Place a primitiveplane

- Extrude planesedges and manipulateindividual vertexes in 3D space.

- Pick a place to

start.


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And adding some details and smoothing and I'm done!

SPEEEEED MODELING!
https://www.youtube.com/watch?v=alhqRVLth6A


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https://www.youtube.com/watch?v=alhqRVLth6A


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End of Modeling Part 1 (3/14 lectures)

3d introductory part 3 updated

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