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Bump Maps and File Formats

Author: elizabyte

Tools Needed

  • Photoshop 5+ (or any graphic program that uses channels)
  • Poser 4+

Support Files


It's commonly believed that Poser 4 cannot use a JPG as a bump map, but that's not true. It can. The problem is that a grayscale bump map such as Poser Pro Pack or Poser 5 uses looks really awful in Poser 4. The issue isn't the file type (.bum, which is actually just a renamed BMP), but with the bump map style.

DO NOTE that in order to apply a JPG as a bump in Poser 4, it MUST be applied via MAT pose. If you try to apply manually, Poser will automatically try to convert (even if pre-converted). Apply with a MAT pose, though, and it works perfectly.


Step 1 - Converting with Photoshop Action


It's beyond the scope of this tutorial to suggest how to go about creating a grayscale bump map. The assumption is that you have one you want to convert for use in P4.

The easiest and best way to make a Poser 4 style bump map is by using the Photoshop Action included with this tutorial. To do that, unzip the contents to the directory where you keep your Photoshop Actions (usually under your Photoshop directory, in Presets:Photoshop Actions).

In Photoshop, load the action by clicking the Actions panel and choosing the arrow in the upper right hand corner, and then choosing, “Load Actions…” and select Make_Bump.atn (may appear as Make_Bump depending on your windows settings).

Open the grayscale bump map and in the Actions panel, click the small arrow beside the Make_Bump action, click the top option (bumpmap), then click the arrow on the bottom of the panel. The action will run and, voila, P4 style bump map!


There are other ways to do the conversion, however, so I'll outline those in the next step for those who don't have Photoshop…

Step 2 - Converting with Poser

You can, of course, also convert grayscale images in Poser 4 or Poser Pro Pack. The steps for doing this are outlined in the DAZ Support FAQ. Do bear in mind that the PC version of Poser 4 (and Pro Pack) has a bug that produces slightly incorrect bump maps. For most things, it's not an issue, but for some it can be quite noticible. (More information on that bug and what can be done about it is also online elsewhere.)

If you choose to convert using P4/PP, you'll need to go to your Poser textures directory and find the converted .bum and open it in Photoshop to complete this tutorial.

Finally, if you can't run the Photoshop Action and you don't want to use Poser to do the conversion, it can be done manually.

Step 3 - Converting manually

Manual conversion is possible with any image editing program that supports channel separation (i.e., that lets you manipulate the blue, red, and yellow channels separately).

The steps are:

1) Select blue channel

2) Fill with black (100% opacity)

3) Select green channel

4) Emboss (Angle: 90, Height: 1, Amount: 100)

5) Select red channel

6) Emboss (Angle; -30, Height: 1, Amount: 100)

7) Select RGB channel

That's it, and it corrects the error that the PC version of Poser makes when creating bump maps.

Now to save the bump and make sure it works in the character, prop, MAT pose, or wherever it's referenced…

Step 4 - Converting existing files to use the JPG

This is where most bump map tutorials will tell you to save the bump map as a BMP and then change the file extension to .bum to be used in Poser 4. And you can do that if you want to, of course, because that's how Poser 4 makes bump maps, but that's not what this tutorial is about.

Save your now-converted bump map as a JPG, with the JPG extension. I recommend saving with a name slightly different from any existing .jgp bump maps that may already be present in the texture directory. Make it something you'll remember and be able to identify easily.

If you are using this technique in the creation of a product (freebie or for sale), you can now just apply the converted Poser 4 style JPG bump as a normal bump map, in the bump channel. It will work exactly the same as a .bum (remember, Poser 4 can apply JPG files as bump maps!), but take up much less drive space since it's a JPG rather than an unweildy bitmap. Furthermore, users of the product won't have to convert anything at all. They can just choose the “P4” version of your MAT poses or character or whatever, and that's all they need to do.

If you're using this for your personal use rather than a product, you'll need to use a text editor to open the file (.pz2, .CR2, .pp2, etc.) that references the bump. Do a search for the name of the old .bum file, and replace all of the references with the name of the newly converted JPG version of the P4 style bump. (Just as a side note, I really like the free software package, Notetab Light for editing files. You can open very large files, no extraneous junk is added to them, and you can open multiple files and do universal search and replace, and you can't beat the price for the software!)

Step 5 - Final Tips

Do remember that you must apply the JPG bump with a MAT pose.

Also, if you ever need or want to open a .bum file in a graphic editor (Photoshop, Paint Shop Pro, etc.), you'll need to change the name of the extension from .bum to BMP, and to save, save it as a BMP and convert the extension to .bum

When I shared this information on a private board for other Poser users, one P4 user said that they had been using this technique for some time. They simply keep the PP/P5 version MAT files, convert the existing provided bump maps (which are, of course, grayscale), and they don't have to edit anything else at all. After using this technique for all of their Millenium people and animals, they ended up saving 2.5 gigabytes of drive space!