Quick render tutorial

Introduction

With this tutorial, we will try to give a fast view of the quick rendering. Through these 10 steps we will have a global vision of the process, always considering that the number of steps can vary, depending on the shapes complexity and the final quality level we want for our work.

Although our intention is to centre this tutorial in Photoshop, we must explain that the process is the same if we work with Painter because the layers work in an analogue way with both tools.

This tutorial does not try to explain with detail each one of the mouse moves, but it starts from the basis that you have at least the basics of Photoshop and is not needed to explain how to get, for instance, a new layer, or what is the use of theLevels dialog box.

Step 1

We can start in two ways:

If we have a Wacom Cintiq graphic tablet we can directly draw over a new white document in Photoshop or Painter. With other types of graphic tablets it can be really hard if we have not the necessary practice.

Or we can start from a free hand on-paper sketch, scanned at the resolution we need depending on the final size and quality we want to give to our final render.

In both cases, the final size in pixels for the image-document must be considered in the same way. As a reference, the original images that accompany this tutorial are around 2300 pixels width, to assure a respectable A3 and a good A4 print quality.

We will not going to explain the way in which the sketch is drawn, thinking that this can be considered in a future tutorial, so once our sketch is on the screen, we can go next step.

Step 2

Start by creating a new layer, and change the blending mode in ‘Multiply’. In this mode, the black colour of the sketch lines (in the background layer) will be visible over the ink of the tools used in this layer.

The colour used in this case was a light cool grey (R=220, G=220, B=230 or something like that). Using a big size brush tool, (Normal blending mode, 100% opacity and 100% flow) we cover all the car nearest area. Do not worry about to paint out of the lines of the sketch, because the next thing to do will be to erase it.

To do this, is highly recommended the use of the paths, because they are flexible and it is relatively easy to adapt them to the car curves and shapes. You can get a complete ‘Use of the paths’ tutorial following this link. Once we got the closed area of a path we can load it as a selection, by Ctrl-Clicking over it at the Paths panel (Photoshop) or using the ‘Convert to Selection1button (Painter). When we do this we get a sharpened edge around the selection area. If we need soft edges we can use the‘Feather’ option from the ‘Selection’ menu. Once the selection is ok we can use the Eraser tool to carefully rectify or if necessary simply press the Del key to completely remove the selected area from the active layer.

To know what to erase, follow a couple of rules:

When using a perspective like the used in this case, we can say that the more perpendicular we see a surface, the more light it will seem. That is because we suppose the light source over our shoulder. So, we must erase the upper frontal viewed surfaces. If the surface is big enough we can represent it as a gradient, from white to the car’s colour, with the white in the most frontal viewed part.

The darkest parts, because they show us the out of the car silhouette. That will help us to see better the result.Do not worry about glasses. Let them at this moment with the same colour of the rest of the car.

Step 3

We can use several ‘Multiply’ layers. In this way we obtain a stronger colour for shadows and the surfaces on which the floor or ground is reflected.

For these layers we recommend to use a much lower brush flow, in the options bar of that tool. We have used only 1% and 2%, with the layer as before, set in Multiply blend mode.

Maybe you think the level of contrast is too low, but you do not worry about it for now. We solve that problem almost in the end.

Step 4

Now let’s take a look at the black and dark areas. One of these are the glasses. They receive a special treatment, because they reflect at the same time that they are transparent.

Since we have previously coloured them, we have got the reflections. We only must change the colour by a contrasted one, for instance dark grey. There are several ways to do that, and we will use maybe the most interesting.

Start by selecting the glasses area with the pen tool to create a path and loading it as selection. Then, will click on the upper layer to mark it. Once selected, we will create a ‘Hue/saturation’ adjustment layer, for instance, by clicking on the arrow at the top-right of the Layers palette, and selecting ‘New Adjustment Layer…’.

In the dialog box we will drag the Saturation control to the min value and after that, we will click in the Ok button. Then we will repeat the steps from the selection of the path, but creating a ‘Levels’ adjustment layer instead the ‘Hue/Saturation’ and dragging the half tones control to the right until we get the desired darkness. Doing it this way we can always come back to change the settings anytime.

To get the rest of the dark zones, as the shadow, the tyres and the interior of the wheel by-pass, we must do like before, by selecting these areas with the pen tool as described. Then we will create a new layer at the top of the list, and we will paint/fill the selection with the desired colour. Do not forget to select again ‘Multiply’ as the Blending mode for this layer.

Now, the glasses will seem opaque, but in the next step we will provide the transparency.

Step 5

To obtain the transparency we will create another layer on the top of the others. Do not forget the‘Multiply’ Blending mode and select a darker grey than the ones used before.

Select the areas that represent the interior of the car which are coincident with the grey colour of the reflex, and paint/fill them with the previously selected colour.

Also the interior of the wheels by-passes are processed in the same way and a double zone is generated in the shadow to emphasize the contour.

Step 6

As the render comes to life, we must define better the surfaces, giving to the encounters between them a greater contrast.

Note how the definition of the exterior of the front wheel arch has gain by adding again another ‘Multiply’ layer.

Create as many new ‘Multiply’ layers as you need to provide more depth to your work.

Step 7

Now we will look at the details. For many of you it may look like an already finished sketch or render, but there are still details that take some time and in the same time they make the car look closer to reality. Anyway if we do not make them, the render will always seem incomplete.

Since this part of the process can be a little bit ’stressing’ you can alternate with other pending tasks.

Note the interior of the front lamp and look its evolution in the next steps.

In this step we have also darkened glasses, to increase the contrast.

Step 8

Depending on the final quality you want for your work, you can add more or less of the car components, like, for instance, logos, brake disks, air in-takes, rear-view mirrors, door handlers, etc. You can add more details of the interior if you want, but do not forget the front / rear lights, because of their current design importance.

Since most of these areas have small surfaces, the work by using paths may not be as quick as we desire. Then you can use normal selections, done with the ‘Lasso’ tool or similar. Avoid to create a layer for each one of these surfaces. Group them, for instance, by colours. Paint in only one layer the surfaces that use the same colour.

Step 9

The final steps of the process are simples but with them you get the most visible results.

At this step, you can save the image with all of its layers in the native PSD (Photoshop) or RIF (Painter) format files. These file formats are useful to save the work. As you know, in these formats you work over a layer at a time, so it can be very laborious to work with the whole image. To work easier from this step, you can save it as a JPG or TIFF file. In both of these formats you manage only one layer with the appearance you had on screen at the moment you saved it.

Be careful of saving the original PSD or RIF file at the final state, because that is the file you must edit in case you still want to make any modifications. However, for this step, we are going to work with the JPG or TIFF file saved as described in the previous paragraph.

Close the PSD/RIF file to avoid confusions, and then open the JPG/TIFF. Once on it, go to Image>> Adjustments>> Levels and drag the half-tones control to the right to give more contrast. You can try the Auto button too. Evaluate the results before closing the Levels dialog box. To restore the original values, press the Alt key and the Cancel button turns into Restore.

Step 10

In this last step we must only add white shine in certain points to simulate spot lights reflected on the car’s edges.

We can do it directly over the background layer if we work with the JPG file, or in a new layer in ‘Normal’ blending mode.

Apply white over the darkest edges of the body using the airbrush tool. You can use elliptical points for it when needed.

You can apply white to enhance the joints of the body, doors edges, bonnet, etc. In such cases is better to mark a white line instead of a point by contouring a path with a small-point brush. Consider to use the ‘Simulate pressure’ option in the‘Contour path’ dialog box to leave fading both ends of the path.

Global tips:

As you can see, the farther zones of the car, in this case the rear, have the colour diluted. That will help us to centre the attention on certain areas we want to enhance.
Sometimes you can get a better result if you put a background localised behind the car which is reflected over it. If you do so, you can use it to draw the car silhouette as well as to get a point more of contrast.
To obtain an even better result you may think about the use of more than one colour. For instance you can select a dark colour (black, dark blue…) for the car’s body and a gradient from a light colour (yellow, orange…) to white for the illuminated surfaces.
Is highly recommended to save the masks of the main car’s areas, as the whole silhouette, the glasses, lamps, wheels… Having them you can always make changes and adjustments of last minute.
One of these changes can be the final hue of the body. To do this you must flatten image (menu Layer) and load the appropriate selection (only the body). Once loaded, go to Image>> Adjustments>> Hue/Saturation or better, create an Adjustment layer (see Step 4) of that type, and select ‘Colorize’. Use the controls to give the body the look you like. Note that if you use ‘Colorize’ you only get a hue for the whole selection. So, if you used several colours, is not recommended to use this process. Try it by disabling the ‘Colorize’ control instead.

Emanuel Derta has two Masters in Transport Design. Winner of a reputed Spanish design contest sponsored by Nissan, works now as a car designer for a known brand.

Download the whole tutorial in a PDF file by clicking here (Right click and Save target as…).

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