Saturday, 12 February 2011

How to Use Pelt Mapping

Posted by Tien Dung | Saturday, 12 February 2011 | Category: |

In this tutorial, I’ll show you how to use Pelt Mapping inside of 3ds Max and ZBrush. It’s very useful feature that will allow you to map objects easily and precisely! It’s definitely worth learning this technique. Let’s see why it’s so great!

Pelt Mapping


Pelt mapping is a very useful method of mapping untypical objects (like organic models, rocks, trees etc.) that are difficult to map in a standard way. It allows you to ’stretch your object’ on a plane and make it 2D. Then you can use other tools like ZBrush to create a great texture that perfectly fits your object. I’m going to use some simplier object here which is just a table. For your convenience I’m going to start with modeling process because that’s also important. Not every object will work here. You’ll always have to add a few more polygons for the simpliest objects in order to have them smoother inside of ZBrush. Take a look at my table which is already mapped.
 

Step 1

To begin with open up 3ds Max and create a box with dimensions like 22 for length, 24 for width and 1,5 for height. Add three lenght, three width and two height segments. Convert it to Editable Poly by right-clicking on it and going to Convert To: and selecting Editable Poly.

Step 2

Press 4 to enter Polygon sub-level of Editable Poly. Select corner polygons and use Inset on them with Amount like 3.

Step 3

Start extruding polygons that are meant to be legs of your table until you create something like this on images below.

Step 4

Now try to select all the edges that are borders of your object. Don’t select any edges inside because we want it to be a little bit chamfered only outside! Use Chamfer on edges you’ve just selected with amount of 0,1. We have to do it because we want to have more control over stroking polygons while increasing thier number inside ZBrush and don’t want to lose original shape what could make our texture doesn’t match with object when we’ll be back to 3ds Max.

Step 5

To check if you’d selected correct polygons you can select Nurms Subdivision. If it still does look correct it means you’ve done that correctly. Don’t forget to deselect it.

Step 6

Add a modifier called UVW Unwrap.

Step 7

Go to its sub-level called Face and select all the polygons that build leg of your table. Now choose Point to Point Seam and draw a line like mine.

Note:
  • You can turn off Ignore Backfacing to select polys easier and on both sides at the same time.

Step 8

Once you finish drawing press Pelt. Notice that there’s a new option available down in the menu called Edit Pelt Map. Turn it on and press Simulate Pelt Pulling a few times. This will make your mesh stretched. You can see what’s going on in Edit UVWs window.

Note:
  • In case the lines are overlapping you should first grab red points, scale them up a little using scale tool and simply redo Simulate Pelt Pulling a few times again
  • If your lines are still overlapping make sure you’ve deselected Select Element option and you can grab some vertices and move them slightly
  • In the event it still doesn’t work you have to draw other route to pelt it because one you’ve selected seems to be incorrect. In this particular case it will work fine.

Step 9

Now your mesh is stretched also in Edit… window.

Step 10

Do the same with the other legs. To stretch table top select all the polygons and again draw a line similar to mine. We can’t close it because if we would do it it will divide our mesh into two parts. Doing it it’s usually good to imagine that you’re cutting your object with knife and blue lines are places where will the hole be. Again use Pelt then Edit Pelt Map and finally Simulate Pelt Pulling a few times. Scale up red vertices if you need to and make sure your lines aren’t overlapping. When you are done close that window.

Step 11

Open up Edit… window again and place all your objects separately in the square with the thick black borders (actually they are dark blue but seem to be black). You can use tools like Move, Scale and Rotate if something doesn’t match.

Step 12

Now all mapping informations are assigned to this object so we can export it to ZBrush and paint that there not losing anything. Go to File -> Export… and export your object as a *.OBJ file.

Step 13 – Inside of ZBrush

Import your *.obj file using Import an OBJ file function inside ZBrush. Now follow my screenshot to select correct ZBrush options. First click on Edit (1). After that choose Fast Shader 5 (2) material from the list to the left. Select MRGB insted of RGB and deselect Zadd. Increase number of polygons by going to Geometry -> Divide. We need them more to paint on that additional geometry. Last thing is to go to Texture and enable Colorize.
Click on the screenshot below to enlarge.

A couple of things to note:
  • Fast Shader 5 can be replaced with anything that allows you to clearly see the material so I think something bright will be great
  • MRGB is a channel enabling you to edit material and not the object itself
  • We’ve disabled Zadd because we don’t want to sculpt mesh but only paint on it (you can sculp your objects if you want to)
  • Click on screenshot to enlarge

Step 14

You can choose any color (1) you like as well as brush size (2) and rotate, scale or move your object the way you need it using icons I’ve marked as 3. Start with painting table legs.

Step 15

To paint over table top press Shift and rotate your table until it will be exactly straight. We can use masks to mask some parts of our table that we don’t want to paint on. To do it press and hold Ctrl/CMD and choose the size of mask. Once you’ve done that you can paint regions you’ve chosen.

Notes:
  • If you lose color you were using press C to get it back
  • Obviously you’ll want to paint your object with normal textures. I’m using these stripes to show you how I’m usually doing it and to show you clearly that it works

Step 16

Once you’ve done that let’s create a texture from that by clicking on Col>Txr in Texture table. A new texture should apper to the left but it’s a bit different than the one from 3ds Max.

Step 17

It is flipped vertically so to flip it back go to Texture and find there option named Flip V.

Step 18

Finally we can export it for instance as a *.PSD file by clicking on the texture preview to the left.

Step 21

Go back to 3ds Max and press M to enter Material Editor. Choose any material slot and put a texture as its Diffuse using Bitmap. Select the table and again go to Edit in UVW Unwrap options. It should fit perfectly but in the event it doesn’t you can move some verticles slightly.

Conclusion

Check if your texture works on renders. If so you’ve just completed this tutorial and I hope you’ve learned something new. Please leave your thoughts about my tutorial below. Thank you!

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