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Subject: Manual creation of BUM bumpmaps


_dodger ( ) posted Wed, 18 December 2002 at 5:44 PM · edited Fri, 29 November 2024 at 5:58 PM

file_36884.jpg

Okay, first, if you don't already know this from following my or others' explorations of bumpmap stuff, including the great Bumpmap fiasco wherein Poser 4 for PC does them wrong, my Tron lines magic BUMs, and my JPEG compressed BUM stuff, a BUM file is just a 24-bit Windows bitmap with a different extension. (I recently tried to hack my registryto make it show up as such even, but I got lost. Bloody Windows ME) Anyhoo... Well, I was reading the Great Bumpmap Fiasco thread and saw how my bumpmaps were all wrong. Normally a bit hard to tell, actually, but hey. Anyway. I have noticed some oddity, however, from time to time, where it seemed the wrong edge was lit. In a pattern, though, it can be hard to tell if you're just imagining it. So I went ahead and tried the invert-green trick and found that it worked fine, except that the whole thing was SDRAWCKAB. Black was high, which it's never suppoed to be. There's an easy way around this, though. Set the bump level to -100% and viola, you have an inverted version, so the invert-green seems to work as long as you also invert the map itself. But, i thought. that's too simple. Not enough for me! I'm a hacker at heart and I had to see what I could do WITHOUT Poser's dubious help. I made a bumpmap of my own by hand. I don't mean a greyscale bumpmap, I mean the green-red contents of a BUM file. I did this: 1) Open your original greyscale bumpmap in Photoshop. 2) Double-click the background to make it a layer. (I hate dealign with a background latyer without a good reason -- I like my layers to behave the same.) 3) Duplicate the layer. You should now have Layer 0 and Layer 1 both with a copy of the bumpmap on it. 4) Create a new layer (Layer 2). Fill it with black. 5) Hide Layers 1 & 2 and go down to layer 0. Run a Stylize->Emboss filter on it. Light it from 135 degrees clockwise (from the upper left in other words). 6) Show layer 1. Do the same, but emboss it from the lower right 45 degrees clockwise. 7) Hide layer 1. Select all and copy merged. 8) change to and show Layer 2, the black layer. 9) flip over to the Channels palette and select the green channel. Click the eyeball box for RGB so you can see the entire thing at once (it will show all channels but you will be working only in green. 10) Paste. 11) click RGB to switch back to all-channels mode. 12) Flip back over to layers. Hide Layer 2 and show Layer 1, your second and lower-embossed version. 13) Select all and copy merged again. Unhide Layer 2 (you should be still in Layer 2, if not, switch back to it) 14) Flip back to channels. Select the red channel and show all channels again. 15) Paste again. Look familiar? If you have opened a BUM as a BMP before, it should. Only perhaps a bit brighter. 16) Switch back to all channels mode. 17) Save as BMP and rename to BUM. In Poser, set it as the bumpmap. (Or you can do the JPEG compressed BUM trick in Poser 4 and hack the .??2 file to point at the JPEg for the bumpmap, but remember this doesn't work for PPP or P5 because it will try to reconvert the JPEG BUM to a BUM, double-BUMming it! -- see my other thread). 18) render. The image in this post was made using a manually created BUM and I think it has a lot better tightness than a Poser-made BUM. There's some 'depression' in the areas in between, but since this was a map for something UVmapped differently, those blank areas in between wuoldn't be on the real model because they are outsie of any UV facets. I think those are some impressively tight bricks, myself! BTW, to get the basic greyscale bumpmap, I did the following: I took the original texture in Photoshop and ran Equalise, then Auto-Levels on it. Then I ran an action I have built for colour stripping that does as follows: Hue/Saturation, colourise mode, to pure red (all the way tothe left) with maximum saturation (all the way to the right) and no lightness asjustment. Next, run Hue/Saturation again, this time not in colourise mode, but select the Red colour range from the dropdown and turn the lightness all the way up (all the way to the right) and don't mess with the main or other colours. This will effectively strip all colour from the image and leave very little of it as a grey tone, which is different from merely converting to Greyscale or desaturating. This I then refined and used as the greyscale bumpmap.


_dodger ( ) posted Wed, 18 December 2002 at 5:50 PM

this one is also manually done, the difference being that I ran a stronger degree of emboss and then ran an unsharp mask on the whole thing. A note -- if you want PPP and P5 users to be able to use these, instruct them to open them in an imaghe program and re-save them as 24-bit Windows BMPs, then rename the .BMP extention to .BUM and they should be able to use them fine.


_dodger ( ) posted Wed, 18 December 2002 at 5:50 PM

file_36885.jpg

would help if I included the image I'm referring to, wouldn't it? B^)


_dodger ( ) posted Wed, 18 December 2002 at 5:55 PM

file_36886.jpg

this is the 'natural' BUM created by Poser, only with the green channel inverted and the whole thing set to -100%.


_dodger ( ) posted Wed, 18 December 2002 at 5:56 PM

I think the ones I made manually look better and tighter.


_dodger ( ) posted Wed, 18 December 2002 at 5:59 PM

file_36887.jpg

This is the same as the one above, only with an Unsharp Mask filter run on the thing to try to get increased crispness as with my manual BUMs. As you can see, it is scriper, but a lot uglier and shows some BUM gamut leakage as per the Tron effects though less extreme. It could be used to simulate metallic bricks, perhaps.


_dodger ( ) posted Wed, 18 December 2002 at 6:04 PM

Finally, I thought I would show an example of what happens when you run a Photshop filter on the whole thing. This is the Poser-native BUM with green flipped and the Coloured Pencil Artistic filter run on it. In all of the renders the lighting and material setting are the exact same, except the BUM file used.


_dodger ( ) posted Wed, 18 December 2002 at 6:04 PM

file_36888.jpg


_dodger ( ) posted Wed, 18 December 2002 at 6:11 PM

Hopefully I've imspired some of you to play with your BUMs! Hmm, amazing what you can say on Renderosity if it's in context.


_dodger ( ) posted Wed, 18 December 2002 at 6:18 PM

file_36889.jpg

Gotta show this one... This is the result of doing like the one above, only instead I used the Plastic Wrap filter. I thought it would turn out crap, and for bricks it has, but is anyone thikning what I'm thinking? This seems an excellent way to make better water...


_dodger ( ) posted Wed, 18 December 2002 at 7:19 PM

file_36890.jpg

Here is the bumpmap in #1 above with the texture applied.


chriscox ( ) posted Thu, 19 December 2002 at 11:00 AM

This is similar to how I use to make BUMs on the fly for files that called for them but only provided a greyscale JPG bump instead. I use less steps than you do by just working with the channels. Go to the Blue channel and fill Black, go to the Green channel and emboss and finally got to the Red channel and emboss. Save as a BMP and then change the extensiopn to BUM. My Emboss angles were differnet but they seems to work just fine. Chris Cox

Chris Cox



chriscox ( ) posted Thu, 19 December 2002 at 11:20 AM

Attached Link: http://www.poserpros.com/forums/viewtopic.php?t=6380

You can go to PoserPros for more details on the steps I used, a copy of the Photoshop 6 action that does this (get the zipped version posted later in thread) and a link to another thread about BUMs Chris Cox

Chris Cox



illusions ( ) posted Fri, 20 December 2002 at 9:46 AM

I discovered the trick of making bum maps for Poser 4 using Photoshop about 2 years ago. Click the link to read the original discussion and see the examples. It's interesting to note that I was using a P100 Win95 PC and black DID indent.


bikermouse ( ) posted Wed, 25 December 2002 at 10:04 PM

Dodger try the green inverter greenthingy I did in freestuff remember your output will be an .out file just change the extension to .bum. any feedback Would be appreciated. - TJ


_dodger ( ) posted Wed, 25 December 2002 at 11:47 PM

I've done some more research on this and found that the correct embossment angles appear to be as follows (Photoshop Stylize-emboss filter for each channel of Red and Green, with Blue filled with Black) Green: 90 degrees Red: -30 degrees For the nicest look I've found that it works best to elarge the bumpmap to 200% first, then do the embossing channels thing with the emboss set to depth of 1 and amount at 100%. Then I run an unsharp mask at 100%, 1 radius, 0 threshold, then I shrink it back to 50% (thus the original size). Inverting green is close, but not quite it exactly.


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