7_3DS Max_UV Mapping Fundamentals Flashcards Preview

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Flashcards in 7_3DS Max_UV Mapping Fundamentals Deck (65):
1

UV Mapping

The 3D modeling process of projecting a 2D image to a 3D surface for texture mapping.

It is the process for creating UV Coordinates. These coordinates tell the 3D software exactly how to cut up the texture map and where to place it on the objects.

2

Cluster AKA Shells

A piece of a UV map

3

Seam

Seams are the edges of a cluster that signify a separation from other edges in the UV coordinates

4

Overlapping

When polygons of a UV map overlap one another

5

Distortion

Distortion is an area where your texture map literally stretches or squashes on the model, skewing the texture

6

Texture Space

The amount of space each UV cluster has within the image size of the texture.

It's important to balance Texture Space between all of the clusters, and to pack the clusters to use as much of this space as possible.

7

Texel Density

The amount of space each part of the texture has or even the UV cluster has.

Larger clusters are going to take up more texture space, thus giving them more resolution.

8

Packing

The process of arranging all of the clusters within the UV space.

There are two types: Automatic and Manual Packing

9

Automatic Packing

Arranging the clusters within the UV space using the Arrange Elements tools.

10

Manual Packing

Moving each cluster, rotating them, scaling them, getting them to fit in this UV space.

11

What are the 5 Basic UV Mapping Concepts?

1.) As few clusters as possible

2.) Minimize distortion as much as possible (it's not possible to get rid of all distortion, know when it's good enough)

3.) Use properly flattened overlapping UV's, but only when necessary. Acceptable when texture is symmetrical. Not acceptable when texture is asymmetrical.

4.) Pack your UV's efficiently while maintaining equal amounts of texel-density. Keep everything at a relative amount of resolution across the entire mesh

5.) Balance all of the concepts

12

What are the 4 types of Projections?

Planar, Cylindrical, Spherical, Box

13

Smoothing Group

Is a group of polygons in a polygon mesh which should appear to form a smooth surface.

Smoothing groups are useful for describing shapes where some polygons are connected smoothly to their neighbors, and some are not.

14

Planar Mapping

(First apply the Unwrap UVW in the Modifier List stack)

Projects UV's onto a mesh through a plane. This projection is best of objects that are relatively flat, or at least are completely visible from one camera angle.


Typically done to select multiple sets of polygons, and then use that planar map projection across

15

Cylindrical Mapping

(First apply the Unwrap UVW in the Modifier List stack)

Creates UV's for an object based on a cylindrical projection shape that gets wrapped around the mesh. This projection is best for shapes which can be completely enclosed and visible within a cylinder, without projection or hollow parts.

16

Spherical Mapping

(First apply the Unwrap UVW in the Modifier List stack)

This will project a texture inwards from a sphere. The texture will resemble the original image the most at the equator. The texture will start to converge as it reaches the poles of the sphere.

17

Box Mapping

(First apply the Unwrap UVW in the Modifier List stack)

This will project a texture of six sides of a cube in towards a 3D model. A texture will be projected from aside of the cube until stretching occurs, then the next best projection side will take over. Box mapping is a quick and easy solution that will work in most cases because there will be minimal stretching of textures.

18

Mixed Mapping

(First apply the Unwrap UVW in the Modifier List stack)

Whenever we use just a single type of projection type it will give us one type of behavior. Mixed Mapping is done so that one can mix to get the exact UV configuration desired.

19

Linear Align

Averages out the extent of the selection, then moves the vertices along that edge, somewhat like a constraint.

20

What are the two types of brushes in the UVW Editor?

UV Paint Movement

UV Relax by Polygon Angles

21

UV Paint Movement Brush

Controlled by the strength (inner circle of the brush) and falloff (outer circle of the brush). The fallout has different modes: fast, slow, smooth, linear

22

UV Relax by Polygon Angles

Ability to relax by edge angles and centers. Similar to the relax tools except with the behavior of using a brush. This can be very helpful whenever trying to relax just certain areas. Good place to use this is on a character's face, on the nose. The nose is a very complex shape on characters and that area can get really distorted when trying to relax that area to try and remove any overlapping faces, this is the brush that will really help.

23

What does it usually mean if there's an odd result in the UVW Editor?

The UV has been flipped

24

Explain the 5 types of Stitching options -

Stitch to Target
Stitch to Average
Stitch to Source
Stitch to Custom
Stitch Settings

Stitch to Target: Red Source side will connect to the location of the Source’s side.

Stitch to Average: Works well whenever clusters are arranged in close proximity of one another. Extends the polygons of both objects to move equal amounts towards each other.

Stitch to Source: Blue Target side will connect to the Red Source side

Stitch to Custom: Ability to align and scale clusters based on a bias value.

Stitch Settings: Available from the Stitch: Custom flyout. Opens the Stitch Tool dialog.

25

What color is Source vs Texture

Source is Red
Target is Blue

26

After adjusting, stitching, and welding a UV map, it's common practice to do what after?

Relax the objects and make sure there are the least amounts of seams.

27

When you are ready to use the Arrange Elements tools are you are ready for what?

Packing

28

What happens if the padding isn't set up correctly?

What number should it be set to?

.005

If the padding is too close to one another, texture bleeding occurs from one UV to another. Especially if the game engine is applying MIP Mapping.

29

What's the difference between Normalize Clusters and Rescale Clusters?

Normalize takes all the clusters in a group and sales them inside the 0 to 1 space as a group.

Rescale is for rescaling individual clusters in proportion to another to make sure they are uniform.

30

Why is it important to have a well done pack?

It's important to use the tools inside of the UVW Editor to rescale the UV maps to fit them in the space taking up the most space possible without deformation. This allows the UV maps to have the best texel density or texture resolution

31

Explain how Grouping works in the Edit UVW panel.

Example 1 -
A bunch of clusters on top of eachother. Then click Group Selected - Pack Custom.The group will fit the UVW space using as much space as it can, keeping the ones that were grouped all together in the 0 to 1 space.

Example 2 -
A bunch of clusters on top of eachother. Then click Ungroup - Pack Custom. This separates them and the grouping is no longer there.

Select by Groups: Click one UV map and the rest will show as selected too.

32

What are some features of Automatic Mapping?

Flatten Mapping
Normal Mapping

33

What are some features of Manual Mapping?

Planar Map Projection
Stitch
Relax
Pack

34

What is the suggested Workflow for UV Mapping?

Automatic Packing - Manual Packaging (packing all together) - Render out a UVW template to prepare for texturing

35

When the UVW Editor is a mess what is the goal and why?

To get all of the UVs of the model laid out flat in order to paint a 2D texture, and apply that 2D texture to the 3D model.

36

Normal Mapping

It's a type of Automatic Mapping.

Checks the normal directions in 3D space, and maps according to those.

The Normal Mapping method of procedural mapping applies planar maps based on different vector-projection methods to texture polygons. It is the most straightforward method, but can result in even greater texture distortion that with the Flattening Mapping dialog. The Normal Mapping dialog lets you control how clusters are defined and mapped.

Will have to follow with Manual Mapping Techniques after.

37

Flatten Mapping

It's a type of Automatic Mapping

The Flatten Mapping method of procedural mapping applies planar maps of contiguous texture polygons that fall within a specified angle threshold. It prevents overlap of mapping clusters, but can still cause texture distortion. The Flatten Mapping dialog lets you control how clusters are defined and mapped.

Will have to follow with Manual Mapping Techniques after.

38

Unfold Mapping

Unfolds and unwraps everything that is selected with 0 distortion, but it creates a lot of seams, and it cannot guarantee the seams will not overlap.

39

What action should you take if there are odd clusters after applying the relax mode?

Select the cluster

Click the Relax Settings again and it should unfold itself

OR

Right click the selected cluster and select flip horizontally

40

True or False

When completing the process of creating a projection map, then relaxing the map, and then realizing that another row or two could have been added to the UV cluster map....you can simply select the map in the UVW Editor, select Grow and select the projection map then relax and the once missing rows will be added.

True

41

What does the process look like for the best practices in creating UV maps for a visor on a helmet of armor? (the armor come off of the base of the helmet and has lots of details on the font of it.)

Select a polygon on the front facing area of the visor.

Under Select By - Click Select by Planar Angle - Change to 75 degrees - Select a polygon - Fill in the rest the need to be filled in on the front. - Correct the boarder to ensure the correct polygons are selected.

Select Peel Mode in the UVW Editor

Select the back side AKA inside of the visor and press Peel Mode

42

When is it a good idea to shrink the size of a UV Map Cluster?

When it's a part that won't be shown much

Example: arm sockets, inside of visor

43

What is the minimum amount of pins allowed in a UV cluster?

2

44

When there are seams in the UV map that you've created that don't need to be there...what is the best action to take to get rid of them?

In the UVW Editor of course...
Highlight all the Vertices in that UV Map - Right Click - Weld Selected

45

What are the options in the Reshape Element Rollout?

Straighten Selection -
Rotates the sides of each selected polygon to absolute vertical or horizontal, whichever is closer. The result is a rectangular grid. Applies only to selected texture polygons. (Great for game hair)
TIP: Works best with grid-like polygon layouts, as opposed to radical layouts.

Relax Until Flat -
Changes the apparent surface tension in a selection of texture vertices by moving vertices closer to, or away from, their neighbors, until all polygons are of an equivalent size. Available at all sub-object levels, and, if no sub-objects are selected, applies to all sub-objects. Relaxing texture vertices can make them more evenly spaced, resulting in easier texture mapping. (Typically done over the entire cluster, unless it's absolutely necessary to relax only certain parts.)

Relax: Custom -
Relaxes the texture vertices using the current settings.

Relax: Settings -
Available from the Relax: Custom flyout. Opens the Relax Tool dialog.

46

What is the Straighten Selection option?

What is an example of an application it works well with?

Name a tip

Rotates the sides of each selected polygon to absolute vertical or horizontal, whichever is closer. The result is a rectangular grid. Applies only to selected texture polygons. (Great for game hair)
TIP: Works best with grid-like polygon layouts, as opposed to radical layouts.

47

What is the Relax Until Flat option?

Changes the apparent surface tension in a selection of texture vertices by moving vertices closer to, or away from, their neighbors, until all polygons are of an equivalent size. Available at all sub-object levels, and, if not sub-objects are selected, applies to all sub-objects.

Relaxing texture vertices can make them more evenly spaced, resulting in easier texture mapping.

(Typically done over the entire cluster, unless it's absolutely necessary to relax only certain parts.)

48

What do the Relax: Custom and Relax: Settings options do?

Relax: Custom -
Relaxes the texture vertices using the current settings

Relax: Settings -
Available from the Relax: Custom flyout. Opens the Relax Tool dialog.

49

Source Side

RED

The original selection of the edge that needs to be stitched together.

50

Target Side

BLUE

Secondary selection of the edge that is to be stitched with the original selection, the source.

51

Under the Explode rollout, what is the Break Tool?

It is used when decided to want a cluster to be stitched elsewhere. Applies to the current selection; works differently in the three sub-object modes. At the Vertex sub-object level, Break requires at least two contiguous edges to be selected, and separates each edge into two. With polygons, Break splits the selection off from the rest of the mesh into a new element.

52

Under the Explode rollout, what is the Flatten by Polygon Angle Tool?

Flattens the UV maps based on the angles of the object.

Using the following settings:

Polygon Angle Threshold
Spacing
Normalize Clusters
Rotate Clusters
Fill Holes
By Material IDs

53

Under the Explode rollout, what is the Flatten by Smoothing Group?

Breaks up the texture polygons using their smoothing group IDs.

When flattening by smoothing group, in order to form a separate cluster, a group of polygons must be fully enclosed by hard edges; that is, polygons that do not share any smoothing group IDs with their neighbors. If some polygons have multiple smoothing group IDs, it's possible that the texture coordinates would not be able to be split into separate clusters.

This tool looks at all the different smoothing groups and breaks them at their seams where the smoothing groups are different.

54

Under the Explode rollout, what is the Flatten by Material ID?

This will only work if there's multiple materials applied to this object or polygons set to a specific material ID.

Breaks up the texture polygons into clusters using only Material IDs. Thus is ensures that no cluster contains more than one material ID after flattening.

55

Under the Explode rollout, what is the Flatten: Custom?

Breaks up the texture polygons using the current Flatten Mapping dialog settings.

56

Target Weld

Doesn't find the average distance.

Combines a pair of vertices or edges into a single sub-object. Available only at the Vertex and Edge sub-object levels.

Turn on Target Weld, and then drag one vertex to another vertex, or one edge to another edge. As you drag, the cursor changes in appearance to cross hairs when it's over a valid sub-object. While this command is active, you can continue welding sub-objects, and change the sub-object level.

When there's a polygon that doesn't look right on a cluster, select it, break it, so that it's not connected the the UV cluster. When it's activated left-click and drag a vertex. Whenever it's held down there will be a blue vertex indicating that it goes together, click and drag to that vertex and it will weld/sew it together.

57

Weld

Finds the average.

Commands the combining of edges on different clusters at the average of their positions.

58

Peel Rollout

The Peel tools provide an implementation of the LSCM (Least Square Conformal Maps) methods of unwrapping texture coordinates, for an easy and intuitive workflow in flattening complex surfaces. This rollout also includes tools for working with the Pin aspect of the Peel Feature. When using Peel, pinned vertices are held in place while the rest of the vertices move.

The Peel tools are available initially only when the Polygon sub-object level is active and texture polygons are selected. The peeling operation you choose applies only to those selected polygons. However, when Peel mode is active, the Peel Mode button remains active and available not matter which sub-object level you activate. You can select different sub-objects while using Peel Mode, but only the texture coordinates that belong to the polygons that were selected when you first activated Peel Mode are subject to peeling. To peel different polygons, turn off Peel Mode, make different selection, and then reactive Peel Mode.

My definition -
Allows the ability to select certain parts of the UVs, much like a projection, then it flattens it out and allows the designer to adjust any distortion might be in the UVs, in a soft type of way. In other words, when the seams are added to the model, you can use the names selection sets to break the model into clusters and lay the clusters out as evenly spaced peels.

59

True or False

Repeated applications of Quick Peel damages the results.

Either.

In some cases, repeated applications of Quick Peel can improve the results.

60

What what stage does it mean if you are using the Arrange Elements mode?

That you are ready for packing.

61

Arrange Elements Rollout

Use these tools to arrange elements automatically in various ways. Packing is useful for adjusting the layout so that clusters don't overlap.

The Pack tools apply only to selected clusters when one or more sub-objects are selected, or to all clusters when nothing is selected.

62

MIP Mapping

A way that game engines down-res textures in order to save memory.

Basically taking the texture at its native resolution and down-reses it based on the distance from the object to the camera. When the texture is down-resed the colors will start to blend. If the padding is not set to .005 then it might go from one UV to another.

MIP Mapping is a great optimization technique that game engines use.

63

When looking in the Viewport, before Peeling and after making the seams. What is a good tool to use to understand the UV maps on the object?

A tool called - Expand Polygon Selection to Seams

This is under the Peel option. Click a polygon then select this tool.

64

What is the Paste Instanced option?

Used for when there are more then 1 similar object/UV map etc. and the exact changes need to be applied to the other. This allows all the changes to synchronize accordingly.

65

What does it mean if words are italicized in the Modifier List?

That Unwrap UVW that is instanced across multiple objects, and so if we change one it's going to change the other