DIY Environment maps – Part 1

Using an environment map for lighting in Photoworks can be a simple method to light both parts and assemblies in a standard way .

I do have a problem though with the environments supplied in Photoworks, as they are all visually very busy, resulting in inappropriate highlights in a rendered model.

What I really need is a simple set-up that replicates a photo studio used for photographing component parts.  I would set up the part on a white continuous back ground with a couple of lights out front and a reflector over head, in this way I could get a clean photo of the model each time.

I can replicate this with a mini studio in Solidworks, and have done, but it can be simpler and quicker to use an environment.

The standard environments do not include a simple studio set up, so I wondered if I could create one. I did some research on the requirements and came to the conclusion that I could do it in Photoshop without taking a single photograph.

I started in Photoshop with a new document 1500 x 750 pixels at 72 DPI and 16bit colour mode. What I needed was a mainly black background with a couple of rectangular boxes to represent the light sources and a reflective area above. The image shown below was what I came up with.

I have one intense light and one less intense and a bit blurred around the edges. The pelmet at the top was my attempt to create a shape that would resolve into a square when laid into a spherical environment.           ( didn’t actually work that well but it still serves its purpose. )

As you may now imagine this is all being done pretty much by guess work so the results may not be optimal in terms of what could be achieved, but hey it did work. This then will be the basis for HDR file that can be created in Photoshop, but also more simply in a program called Photomatix basic.

To create the HDR file you need several images that represent what a camera would have taken with over a range of exposure settings. I created 3 16bit files one at nominal and then one effectively 1 stop higher and then another one stop lower. These images shown below have the RGB values for the 4 elements in the image shown below to give you a starting point for your own trials. The files were created by copying the original twice and then adjusting the RGB value for each of the elements in turn.

RGB Values

Pelmet 237,237,237
Window L 255,255,255
Window R 237,237,237
Background 71,71,71

RGB Values

Pelmet 172,172,172
Window L 244,244,244
Window R 216,216,216
Background 29,29,29

RGB Values

Pelmet 75,75,75
Window L 230,230,230
Window R 179,179,179
Background 18,18,18

When the images are complete you can either take them into ‘Merge to HDR’ in Photoshop or open Photomatics basic and process them there. I tried to do it in Photoshop but couldn’t get on with it so I used Photomatix (www.hdrsoft.com), and that is what I shall use for the rest of this exercise.

This is the opening screen for Photomatix.

Go to file and open the 3 files that have been

generated in Photoshop, and then click on

‘Generate’ under the HDR menu item.

Make sure the radio button is on ‘opened images’ and click OK.

The 3 images should then be brought up in order as they are above, you need to adjust this value,

I used 2.5 as that seemed to work.

Click through with the defaults on this next screen

This screen shows the generated image and allows you with a magnifying box to examine the image.

Finally save the file to your hard disk where you can find it again. It might be wise to save it here
C:\Program Files\SolidWorks \SolidWorks\data\Images\textures\background\
where all the other HDR files are kept.

If you would like to try the the file created here you can email me and I will send you a copy.

In part 2 of this feature I will go through the steps needed to use the file you have created.

impressed me

This is to be a weekly round up of sites I have found that I think are worth a visit. They are not all related to topic, but I enjoyed them any way.

This first one is Photoshop related and illustrates an excellent and easy to use technique for improving your photo’s.

I needed a blood pressure chart the other day and a search of the internet found this, its really comprehensive and helps to explain your BP very clearly.

I wish I could do this, just so impressive.

I love to see animations of mechanisms and engines, this site has them all done in 2D.

making an impression with solidworks Part 3

Before we can start with the rendering in Photoworks we need to set up a new folder into which we can store the materials that will be used in this project. This of course is not always necessary as you can set up a standard folder with the materials and finishes that you will generally use. In this case I have created a folder at C:/Colours/Photoworks Colours/Toothpaste. I like to keep these specials separate from the normal Solidworks directory structure just in case the settings get lost at some point. (As you can guess this has happened in the past.)

When this directory is in place we can have Solidworks access it by clicking on the Material in the Photoworks Items column on the Right side of the screen, and then clicking on the ‘Add file location symbol’

Now we can start adding materials to the model and saving them to the toothpaste directory, but before we can do that we need to identify the colours that we are going to use. I have decided to use a scanned image of a label from a toothpaste dispenser for this project, so the colours are going to be taken from that. I have used ColorCop for this purpose as it will store the colours in a column on the right side of the ColorCop window and display the RGB values. You can configure this small application to stay on the top of the screen so you can have it visible whilst you enter the RGB values into PhotoWorks. The picture below shows the ColorCop window open beside the model and the Actuator part highlighted.

Having identified the part we wish to apply the material to we now need to open the materials menu which is shown below.

This opens the menu and allows us to enter the RGB values for the colour to be used on the actuator. There are a lot of setting that can be made here but we are only concerned at the moment with colour the illumination and then saving this to the toothpaste directory we set up earlier. I managed to clip off most of the bottom box where the RGB values are typed in, but you can just see the value for red at the very bottom. Add the other two values as well for green and blue and the click on the illumination tab at the top of the menu.

The Illumination dialogue collects the information that determines how the surface will react to the light shone on it, so if it is highly reflective plastic or metal surface, clear glass or textured, all of the settings are contained here. The setting shown below will give a reasonable impression of a gloss plastic without being over the top. We are not trying to create Photo realism with this render, so we don’t need highly reflective surfaces that white-out when rendered, but we do need to see and understand the construction of the model we are rendering.

Now that the material has been defined we need to save the material we have created to the toothpaste directory. To do this go back to the original Color/Image tab and click on save ,find your directory and save the material.

Once you have colours defined and appearing in the Photoworks Items menu on the right side of the screen, you can use that menu to drag the colour onto the part, but you do need to define the colours first. I have shown below how you can drag the yellow coloured material onto the flexing piston.

In the next instalment we will get to apply the label (Decal) to the tube and then render the images.

Capturing colours

There are a couple of small applications that make it a lot easier to capture the colours you want to use in your render.

The first is Faststone Capture this lets you grab a section of the screen and save it to disk. This can be used to capture colour pallets that you can then use in conjunction with ColorCop. This has an eye dropper tool that can capture around 8 separate colours from any whereon the screen.

Using these tools in combination you can capture a pallet or any other area of colour with FastStone and then use ColorCop to capture the individual RGB values.

ColorCop will stay on top of other running applications so that it is visible whilst using Photoworks so you can copy the RGB values into the Photoworks pallet. This is a great time saver and very accurate, just a pity Photoworks doesn’t have its own Eye dropper tool, but then that would be too easy.

ColorCop shown here sitting on top of the Photoworks screen adjacent to the colour pallet with the RGB values shown.