Using 3D as a starting point for a Digital Painting

Over the course of this tutorial I shall be discussing some methods and techniques used to create a digital painting of an interior. More specifically I will aim to show how 3D software can be used as a useful application in the process.

Introduction

With a good deal of artistic output these days being produced entirely in a digital format, the tools that artists now have at their disposal have developed far beyond the realms of pencil and paper (although these still prove to be the consummate materials at the birth of an idea).

From concept design to polished production pieces and certainly matte painting, the modern day artist would be hard pushed to avoid working without the aid of tools such as the ubiquitous Photoshop, and Painter. With this in mind, it follows that 3D programs such as 3DS Max, Maya and XSI, etc. offer a number of useful assets that can help inform and solve artistic issues, such as perspective and lighting.

When it comes to drawing even a relatively simple scene that incorporates a few tricky shapes and curved forms, it can take a concentrated session to construct the perspective accurately by hand. By using a 3D package however, a simple representation can be built in a short time and a camera placed in the scene. This enables a swift mock up of the proposed composition and angle of view, but more importantly allows the artist to achieve an exact and authentic "perspective template". By moving the camera the artist now has a completely flexible method of experimenting with the composition and altering the viewpoint, as well as altering the camera settings to exaggerate and distort the perspective slightly and thus change the mood and impact of the picture.

The following tutorial will aim to show how, with the use of a 3D package, a simple scene can be built in order to establish an accurate perspective guide for painting.

Concept

Once you have decided on an idea for your scene, I find it is always best to start with a sketch to explore and clarify some of the concepts. For this tutorial, I essentially wanted to describe a rather grand interior that included a statue as a focal point with a glass panel roof and an interesting staircase. I wanted to try and achieve a Victorian quality about the scene that somehow spoke of a bygone era but with an air of ambiguity about it. I particularly liked the notion of using light to add drama and including a polished marble floor and ceramic bricks which the Victorians liked to use.
Due to the nature of this tutorial I did not spend too much time getting the perspective correct as this was going to be achieved in 3D, but rather just drew in some of the essential components which would later be modelled.

Building the 3D Scene

Once I had finished the rough sketch (Fig.01) I then moved to 3DS Max to build a simple version of my drawing.

Fig. 01 - Click to Enlarge

Fig. 01 - Click to Enlarge

The first step was to construct a simple box that represented the walls and floor and then build the staircase and plinth. I also used a simple cylinder to represent a column with some variation to ensure the perspective was correct for details that could be added along its height (Fig.02). As I was building the scene I thought it might be more dramatic to have the statue and plinth directly below the raised platform, almost as though it were supporting it, which was something I had not planned in the sketch. One other alteration I made was to add a curve to the staircase which added some interest to the composition.

Fig. 02

Fig. 02

The next stage was to put the staircase lamp in and put on the roof, which comprises of two long panelled, glass curves. In order to paint the iron framework I added the relevant number of subdivisions along the roof geometry which could then be used later to create an accurate structure and perspective.

I assigned a plain grey material to everything in the scene as we are only interested in the forms at this stage. By ticking the Wire checkbox in the material editor, the wall and ceiling geometry now display the individual polys, which is very useful as a perspective guide when adding further detail later on (Fig.03).

Fig. 03

Fig. 03

Another area where the use of 3D is particularly useful is in solving repeatable patterns in perspective, and in this case the floor tiles. I created a single tileable texture of a single tile which I then mapped onto the floor. Then in Max I altered the tiling amount to get the right scale (20 x 20) and rotated the angle of the map by 45 degrees, as seen in Fig.04.

Fig. 04 - Click to Enlarge

Fig. 04 - Click to Enlarge

When the scene is rendered, it now creates a very quick and accurate template which can be masked later and used as an overlay in the painting stage (Fig.05).

Fig. 05

Fig. 05

Starting the Painting

Before starting with the painting phase, decide on the size and proportions of the final image and then render out your 3D scene accordingly.

One thing that I briefly touched upon earlier was the notion of lighting. I have not decided to set up any lighting in the scene as I find it sometimes restricts ones artistic freedom. Lighting is a crucial aspect to any image and, as such for the sake of aesthetics, it is nice to be able to bend the truth a little, and in this case use it as a structural device which does not always comply with science! For this reason, I did not spend time setting up a perfect solution but rather used the 3D render purely for providing the perspective.

When you have decided on a satisfactory aspect, render out the image and open it in your respective painting program - in this case Photoshop.

I always keep this render on a separate layer as reference and immediately add a new one that will form the starting point of the painting.

This first layer will be a tonal version of the entire scene and will establish the light source and generally flesh out the light and dark passages in the painting (Fig.06).

Fig. 06

Fig. 06

You can see in the picture that I have worked across the whole of the canvas and assumed a light source above the glass roof. Because I find lighting to be a key factor in most images, I often find that working in a purely tonal way to begin with means that I can determine how successful this aspect is early on, before adding any detail. I have found that if the lighting is right then colour can be added on a new layer set to Soft Light or Overlay later on, and doesn't interfere.

You will notice in Fig06 that I have used predominantly three brushes to block in the tones. I try at this point to keep the strokes quite loose but still retain enough control to define the forms. I use brush 3 to provide the hard edges such as the column and ceiling, brush 2 to add a subtle variation to the surfaces that may suggest wear, and brush 1 to add a texture which may describe stone work.

You will also notice the very crisp edge to the oval floor plinth which was obtained by only rendering out these top facing polys on a black background in Max.

By rendering separate elements, such as those shown in Fig.07, you can then use these templates to save specific selections which will enable you to make quick colour and tonal changes later during the painting process.

Fig. 07

Fig. 07

The way this is done is by first rendering the selected geometry and then pasting this into the PSD as a new layer. You then use this to make a quick selection mask which can then be saved, as shown in Fig.08. On the Menu bar, click Select - Save Selection, which opens a dialogue box, and then name the selection  (which in this case is the Glass ceiling). This is now stored as a new channel which you can see in the Channels palette. You can follow this procedure as many times as you like and when you want to work on certain areas, click on Select again and this time choose Load Selection and then scroll through the list to the desired channel. You can see under "New Channel" in the Save Selection box that there are also three further radio buttons: Add to Channel, Subtract from Channel and Intersect with Channel. Once you have an area selected you can use these functions to modify selections, e.g. masking the foreground objects separately, such as the staircase, column and lamp.

Fig. 08

Fig. 08

These new channels can often come in handy later when you want to experiment with final lighting adjustments and colour variations without the need to manually mask intricate areas.

Now that we have covered the aspect of channels and rendering elements, I think it is time we added the main feature in our scene: the statue!

I had no specific idea in mind except that I wanted a rather heroic stance and dynamic posture that looked somewhat defiant (Fig.09). I decided that a character with his arms stretched upward could always be modified to appear to be supporting the staircase.

Fig. 09 - Click to Enlarge

Fig. 09 - Click to Enlarge

I made the decision to have the statue look very white at this stage to imbue it with an ethereal quality, even though unrealistic. By copying this layer and flipping it vertically it becomes a quick and accurate reflection when set to an Overlay blending mode. I also added some definition to the steps and column as well as the glass roof.

Now it is time to start building on what we have so far and, perhaps more importantly, adding some colour.

The Floor

Before painting in a colour layer I am going to add something which would be difficult to paint accurately: the floor tiles. If you remember last month, I made a simple texture that I mapped onto the floor area and tiled a number of times until the scale looked right. Now it is time to export that floor from the 3D scene and paste it into our PSD file. It is no good simply hiding the objects in the scene, such as the plinth and staircase, and then rendering the floor, as this will reveal areas that are actually hidden in the painting behind and below the said objects. A handy tip is to select all the geometry in the scene, barring the floor, and apply a brightly coloured material as seen in Fig.10.

Fig. 10

Fig. 10

Here you can see all the objects in the scene have been assigned the red material in the Diffuse slot above the scene, except the tiled floor. You will also notice that I have turned the self illumination up to 100, which effectively erases any shading and gives the objects a pure, intense value. After rendering, we now have an image similar to Fig.11.

Fig. 11

Fig. 11

You will notice that everything is red, apart from the floor that is, and so it will be easy to select. As a matter of interest, the doorway appears black because this is the default background colour in the scene. If I wanted to delete this I could substitute this black with the red colour on the objects, thus rendering it invisible, but in this case it was unnecessary. We now have a ready masked floor which we can copy into our 2D scene. After pasting this render into our PSD, set the blending mode to Overlay and you have a tiled floor in perspective that doesn't obliterate the brush marks on the black and white layer (Fig.12).

Fig. 12 - Click to Enlarge

Fig. 12 - Click to Enlarge

Some Extra Detail

We are at a stage where we are almost ready to add some colour, but before we do there are a few more details I wish to add. The walls at the moment look a little simple so I am going to add some small alcoves, as well as some panelling and architrave around the room (Fig.13). You can also see that I have added some handrails around the raised platform, a metal framework to support the glass skylights; as well as some spikes around the statue. The spikes and window frame were rendered from the 3D scene, as demonstrated in Part 1 of this tutorial (last month), but I opted to paint in the handrails and wall detail in Photoshop. One other aspect that I extracted from the 3D version was the top of the lamp stand that holds the four glass lights, to which I added some simple shading and highlights. Other areas that were refined were the stonework on the staircase and the doorway below it. All of this detail was added in black and white on the same layer to keep things simple and consistent.

Fig. 13 - Click to Enlarge

Fig. 13 - Click to Enlarge

Adding Colour

There is a sufficient amount of detail for us to now begin the colouring phase. First of all, create a new layer and set the blending mode to Soft Light, or alternatively Overlay, depending on your preferences. You can see in Fig.14 that my new layer is named "colour" and you can just make out in the thumbnail that the floor is a pale yellow and the walls an olive green. You can see that I have added some variation on the stone staircase and erased some lines into the walls to suggest tiling or stonework. As mentioned earlier, this technique adds colour but maintains the tonal range in the black and white layer.

Fig. 14 - Click to Enlarge

Fig. 14 - Click to Enlarge

I decided that I would eventually have the sun positioned somewhere left of the scene filtering in and across the room, so it would follow that there would be some highlights on the right wall. I added a new layer which I naturally named "highlights", and using a custom brush and a pale grey painted in the main reflection on the right wall, as seen in Fig.15.

Fig. 15 - Click to Enlarge

Fig. 15 - Click to Enlarge

I also added some bounce light on the staircase and left wall, making sure to set the blending mode to Overlay. One useful and quick way to get some randomness to the highlights is by using Select > Colour Range along the menu bar, and then using the colour dropper click on an area and turn down the fuzziness slider, as shown in Fig.16. This way you can select subtle colour variations that provide selection areas for a highlight.

Fig. 16

Fig. 16

Click OK and then fill in with an off-white and the result is similar to Fig.17. You can see how this compares to Fig.14, giving the walls a far more polished look as though covered in ceramic glazed tiles, which was the initial intention. You will also notice that I have unhidden the handrails and given the statue a yellow/green hue to reflect the general colour scheme of the room and help locate him.

Fig. 17

Fig. 17

Let There Be Light

The painting is slowly coming together but the lighting still needs some work to help bind the environment. The first step is to add a new layer which will blend from a white to a pale blue and encompass the glass skylights, as seen in the upper left image in Fig.18.

glass_skylights_fig18=.jpg

glass_skylights_fig18=.jpg

Fig. 18 - Click to Enlarge
You can see that there is a white outline around this, due to a glow effect which was added on the black and white layer (see Fig.08). Now set this new layer to Hard Light, which will reveal the framework and add a blue tint to the right section to reflect some blue sky outside. The left side is partially engulfed by the white so as to suggest a strong light source. The next stage is to add a Layer Effect by clicking on the small "f" icon at the bottom of the layers window and selecting Outer Glow. This brings up a dialogue box, as seen next to the lower left image. Here you can control the colour and extent of the glow which will serve to exaggerate the intensity of the sunlight. In this case, I have chosen a subtle yellow and only used it lightly (28% opacity) as it is easy to overdo this effect. The sunlight now looks a little brighter and we can see it reflected on the right hand wall, but to help give the room a feeling of antiquity and age we can suggest a partially dusty atmosphere. This we do by adding some volumetric effects in the form of sunbeams catching the air particles, common to interiors penetrated by bright sunlight. I loaded the saved selection areas that make up the foreground objects in a manner similar to last month's tutorial, i.e. the statue, staircase, plinth, handrails and column. I then inverted the selection, and on a new layer made some large general brush strokes in a pale yellow with a low opacity, sweeping from the window to the lower right. I then applied some Gaussian Blur until I arrived with something similar to Fig.19.

Fig. 19

Fig. 19

One additional feature which is required is a highlight across the floor and wall where the sunlight is streaming in. This once again was done on a separate layer set to Overlay mode with a little blurring applied (Fig.20). To finish off I darkened the statue and added some shadows to help integrate it into the scene. One last touch was to add some lights around the plinth using the outer glow layer effects we touched upon before. Obtaining the reflections was a simple case of copying and flipping the layer and altering the blending mode.

Fig. 20 - Click to Enlarge

Fig. 20 - Click to Enlarge

It is now time to hone what we have so far by painting in extra detail and fixing the lighting aspects.

Colour Adjustments

The picture at the moment looks very green, which is something I am going to change using an Adjustment Layer. Go to Layer > New Adjustment Layer > Colour Balance; I have shifted the overall colour scheme to create warmer tones (+33 towards the Red and -16 towards Yellow (Fig.21).

Fig. 21

Fig. 21

Before applying the adjustment layer I flattened the file to keep things simple. Some extra detail I added at this stage was the suggestion of a corridor in the background by putting in some wall lights as well as some light filtering across the statue base (Fig.22).

Fig. 22 - Click to Enlarge

Fig. 22 - Click to Enlarge

I painted in the sunlight on a separate layer so it could be blurred slightly in order to evoke a bright highlight.

Adding Detail

The next step was to address the vaguely defined walls by adorning them with some ornate panelling and arches. In Fig.23 you can see where I began to block these in and you will also notice that I have added some highlights along the stone column and corrected the perspective along the bottom section.

Fig. 23 - Click to Enlarge

Fig. 23 - Click to Enlarge

The scene looks a little more interesting but the statue and platform are still lacking, and the scene as a whole appears too monochromatic.

The next stage involves adding three new layers, which can be seen in Fig.24.

Fig. 24

Fig. 24

The first layer is set to Soft Light and introduces some colour variation to the image, namely the platform and the flags in the upper right. The second layer incorporates the four spotlights poised above the statue. I applied a Layer Effect - Outer Glow - to these using an orange colour, in the same manner as the plinth lights below. The third and final layer (set to Screen mode) adds further clarity and highlights to the gilded panels in the background. I also made some refinements to the sculpture as it is the focal point. The platform has now been adorned with a decorative motif that helps emphasize it in the room, but to make it appear more impressive it requires some polishing...

In Fig.25 you can see how it now shines above the statue, almost like a halo. The other changes I have made are concentrated mainly around the back wall where I have added some more definition to the pictures, and panelling as well as the left wall where the light is focused. I also painted in some diagonal lines - dissecting the spotlights - which I then "motion blurred" a little to help increase their intensity.

One last aspect which needed addressing was the contrast between the light and dark areas in the image which seemed a touch too strong. In order to give the scene a sense of age and of strong light filtering through a dusty space, I added a new Curves adjustment layer - the result of which can bee seen in the image below.

Fig. 25 - Click to Enlarge

Fig. 25 - Click to Enlarge

Final touches

The picture is almost complete, but there are a few more minor improvements that could finish the picture... The column and lamp still look somewhat sketchy compared to the statue and plinth, and the arch above the door also looks rather unfinished.

I will now flatten the file and add one more layer which will contain all the extra details which should improve things.

Fig.26 shows the final picture with some tidying up around the lamps, and numerous subtle highlights which do not appear too obvious at first but collectively help bind the scene together more. If you compare this image with the previous version you can hopefully see the differences and how they have helped.

Fig. 26 - Click to Enlarge

Fig. 26 - Click to Enlarge

Conclusion

I hope this exercise has been interesting to those of you who have not used 3D as preparation for a 2D piece, before. It is true to say that the picture could have been done without using 3D software, and that some may argue that it may have been more dynamic by way of a less concise and accurate approach. However, I hope what I have proved is that the application of 3D packages does not necessarily create better images, but can at least be a useful tool in constructing and experimenting with perspective and establishing quick solutions, in the case of the floor.

Simple textures could also have been mapped along the walls to provide stonework and so on, and placing lights in the scene could also have been exploited to provide realistic effects if need be.

The use of 3D is not to everyone's taste, but in this digital age when so much painting is done on computers, the rift between the two disciplines is getting far closer. It seems as though more people are finding themselves embracing both in order to achieve better results, no more so than in the world of matte painting.

To see more by Richard Tilbury, check out Digital Painting Techniques: Volume 4
Digital Painting Techniques: Volume 5
Digital Painting Techniques: Volume 7
Beginner's Guide to Digital Painting in Photoshop Elements
Beginner's Guide to Digital Painting in Photoshop
Photoshop for 3D Artists
and Prime - The Definitive Digital Art Collection

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