Is it possible to make straight strokes using Multibrush tool? Holding shift changes tool temporarily to Line tool instead.

No.

You can use the "parallel ruler" assistant in conjunction with the "multibrush tool"

In fact you can use any assistant with the multibrush tool, but the "parallel ruler" is easyer, because you don't have to match the assistant with the "multibrush tool" center to draw perfect concentration lines.

You can also use the "vanishing point" assistant alone to draw the lines one by one. But you will loose the symetry.

I am sorry artur89sd but how is the assistant tool gonna help me draw a straight line, i can make guide lines with assisstant tools but i cant possibly follow this lines with pen. Am i missing here something ?

Rafal_86 wrote:I am sorry artur89sd but how is the assistant tool gonna help me draw a straight line, i can make guide lines with assisstant tools but i cant possibly follow this lines with pen. Am i missing here something ?

Create an assistant. Any ruler will work.
Select the "Multibrush tool"
Look for the "Tool options" docker
Mark the toolbox "Snap to Assistants"
Draw.

Ow, there is a snap option there ! I did not notice it. Thanks.
But it is confusing option. It does not say Snap to assistant.
It has [Snap single] with checkbox and i had that checked. It does not snap though untill I check the box above it which just say [Assistant]. Would be more clear to make ti Snap to assistant and then below Snap single.

Thank again, that is very helpful information.

My bad.
On the latest beta of Krita it says "Snap to Assistants"

When you have multiple assistants, "Snap single" keep the brush stroke atatched to a single assistant.
With "Snap Single" unchecked, the brush stroke will switch to the closest assistant while painting.