The Quick Answer

The quick answer is that you can use the b hotkey to interactively adjust the source brush size on the fly as you are working. To do this, you hold down the b key and then mouse down in the canvas. You can then draw an interactive dashed line to define the new source brush size you want. When you release the mouse the source brush will be adjusted to the size you specified.

If you are using a Wacom pen, you can adjust the current eraser preset’s brush size by using the b hotkey as described above with the eraser tip of the pen.  Using the normal drawing tip end of the pen with the b hotkey will adjust the current active paint synthesizer preset the same as if you were using a mouse.

The Long Answer

The actual brush size you  end up painting with is a function of several different parameters in the paint synthesizer. The source brush size is a maximum brush size that can then be modulated manually or interactively depending on the parameters specified in the Brush Modulation control panel. So the final sizing of the brush when you draw is a function of 2 different control panels, Brush Source and Brush Modulation, as well as potentially how you use an interactive modulator like pen pressure or tilt when you are drawing.

Let’s run through an example of how this all works. We will start with the Default : Utility : Bristle Paint-Flat preset. If you import this preset and look at the size specified in the Brush Source control panel in the paint synthesizer, you will see that the brush size is set to be 32 by 32 pixels.

If you now hold down the b hotkey you can interactively resize the source brush in the main draw canvas as shown below.

The length of the dashed line you are drawing out with the mouse will be the new source brush size. This is the maximum brush size, so the actual brush size you end up drawing with will be based off of this maximum size and the parameters associated with size modulation in the Brush Modulation control panel.  

As shown below, the Horizontal and Vertical Size parameters in the Brush Source control panel have been resized to match the new size i interactively specified when using the b hotkey.

I could have just gone to the Brush Source control panel and manually edited the Horz and Vert Size parameters to resize the brush. The b hotkey is just  an editing shortcut that allows you to do this on the fly by interactively drawing as opposed to editing sliders or numeric edit fields.

The screen snap below shows what happened when i used the mouse to draw with the resized preset.

The brush appeared to get larger, but it only seems to be half the size i interactively specified for the source brush. Why is this the case? The answer can be found when we look at the parameter settings in the Brush Modulation control panel shown below.

The brush size is being modulated by the path pressure from 0 to 100%. But i was drawing with the mouse, and since the mouse doesn’t have interactive pressure modulation it is defaulting to 50% modulation. If i use a pressure sensitive pen and tablet to draw as shown in the example below note that the maximum brush size when i press the hardest is now matching the maximum size i specified for the source brush above.

Option b Resizing

Some paint presets have what can be thought of as a virtual brush. Virtual brush means it may appear to you that you have a large brush size but the actual source brush might be tiny and something like Path Randomization is shifting the positioning of the small source brush on the fly as you draw to simulate the appearance of a much larger ‘virtual’ brush.

The example below shows a 12 pixel source brush on the left and a much larger virtual brush on the right created by path randomization of the small source brush.

If this is the case, then when you want the virtual brush to get larger you might actually want the path randomization that defines the size of the virtual brush to get bigger as opposed to the source brush itself getting bigger. There are some ReRender parameters located in the Vector Output control panel in the paint synthesizer that can specify which of these 2 resizing options occurs when a paint preset is ReRendered.  

You can manually rerender a paint preset by holding down the option and b keys to interactively resize a paint preset. Instead of just resizing the source brush, option b runs the rerender code for the paint synthesizer. The rerender algorithm will look at the rerender settings specified in the Vector Output control panel when it resizes a brush. So if you have specified a Microstructure rerender Scaling option when you created a paint preset that is using a virtual brush then whatever is creating the repositioning of the source brush will be scaled as opposed to the size of the source brush itself.

Rerender resizing also rescales any internal procedural textures associated with a paint preset. So it could potentially be adjusting many more parameters than just the source brush size. And in the case of virtual brushes we discussed that are created with source brush positioning microstructure, the source brush size may not be adjusted at all when the preset is rerender resized.

Someone asked about how to create a PASeq action step that could zoom the canvas in or out in a controlled fashion. You could of course use the Scale Uniform Interactive Warp to do this. Another approach is to build a MSG preset that scales the canvas. This is an extremely simple MSG preset to construct and we’ll detail how to build it here.

If the MSG Advanced Editor is not currently up in the interface use the Window : MSG Advanced Editor menu to bring it onto the screen. I have configured one of my custom workspace memories for MSG Editing so it’s easy for me to use the menu command key to switch my workspace on the fly for MSG Editing as shown above.

Make sure the Processor Chain (PChain) tab on the bottom left editing list is active. Empty out the processor chain list by selecting the existing processors one by one and pressing the delete key to delete them.  

Now you need to construct your new MSG scaling preset.  You can do this by adding one 3CRotateScale processor to the Processor Chain list. To do this, select the Source (Src) tab for the right side list in the MSg Advanced Editor. This will bring up the processor source library when the Processor Chain is active on the left side. Scroll the processor source list until you get to the 3CRoateScale processor. You can also type characters when the list is active to automatically scroll the alphabetical processor list to the processor starting with the characters you typed. Select this processor and drag and drop it over to the Processor Chain list. You should now see 1 3CRotateScale processor in the processor chain editor.

Select the 3CRotateScale processor in the Processor Chain Editor. Then select the Parameter (Parm) tab in the context sensitive right side editing area. This will bring up the editable parameters for the processor you selected.  This particular processor can scale and rotate an image. Since we are only interesting in scaling and not rotating we want to make sure the Angle parameter stays set to 0. I locked this parameter as well as the H and V Center parameters to insure this would be the case. The Scale parameter is what will define the zoom in or out. Make it negative to zoom in, positive to zoom out. The Bound parameter determines whether the borders reflect or tile or do nothing when scaling out. 

Now select the IO tab in the context sensitive right side editing area. This will bring up the IO (input-out) connections. You need to set these up properly so that the processor takes the Src image Streams as inputs and the Out image Streams as outputs.

The screen snap above shows the correct assignments for the Bus Streams for the various IO Ports for the selected processor. If your IO connections are different, you will need to adjust the Bus Stream connections for the various Ports to match the configuration shown above. This configuration takes the RGB Src streams as inputs for the processor and uses the RGB Out Streams for the output from the processor.  

If you don’t match up the color stream correctly (placing a B Src for the In R port for example), then the output image coloring will not be correct. You can try this to see the effect if you wish. Another potential problem would be to connect the Out Steams to the In Ports. Try this if you want and you will see the result of a recursive IO connection for a geometric distortion processor type (useful for special effects sometimes but technically incorrect)

Depending on the current state of the Bus when you started editing this preset, you may be missing the Src streams. If this is the case, you can edit the Bus to add them prior to adjusting the processors IO connections. To do this, you would select the Bus tab for the lift side list. You would then select the Source (Src) tab for the context sensitive right side area. This would bring up the Stream source library. You could then drag the individual Src streams (R Src, G Src, B Src) from the stream source library to the Bus list.

You will notice that when i checked the current Bus list when putting together this example i had an additional ColorGradient stream in my MSG Bus list. I didn’t need to include this additional Stream since it’s not used in the preset i built. But it doesn’t cause any problems to have it there.  Since it’s not connected to any of the processors in the Processor Chain (just 1 processor in this particular example) it’s just ignored when the preset is run.

There’s one more thing you should check when building or using a MSG preset. All of the controls associated with building a MSg preset are in the MSG Advanced Editor. But how the MSG preset interacts with the current source and canvas in Studio Artist is controlled in the normal generic Editor palette. So you will need to go to the generic Editor palette when in MSG operation mode and make any adjustments there depending on how you want to use the MSG preset. You can always use the Operation : MSG ; MSG generic menu if you are unclear on how to switch the operation mode to MSG and bring up the generic Editor in the interface.

Looking at the screen snap of the Editor settings above we can see that the MSG Preset’s IP Source is using the Source Image as the source for the MSG processing. If you wanted to process the existing canvas image instead you could switch the Ip Source parameter to Current Layer. You also have additional parameter options for Mix and Compositing the effect into the existing canvas. These controls mirror the standard compositing functionality you see in other Studio Artist operation modes like image processing or the texture synthesizer.

When you export a MSG preset the generic MSg parameters shown in the generic Editor palette above are stored in the preset file in addition to the advanced MSG parameters that define the modular architecture of the MSG preset.

msg zoom preset